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CVE-2026-11856

CRITICAL 9.8 ALL-YEARS

Published 2026-07-03 · Last modified 2026-09-15 · curl · NVD: Modified

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.7%chance of exploitation in 30 days · 52nd percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation poc, automatable yes

Impact if exploited

9.8CVSS 3.1 · CRITICAL · ADP

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Curl Haxx

Products Curl

Weakness (CWE)

  • CWE-294: Authentication Bypass by Capture-replay

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References and research data (JSON)

Vendor product assessments

Showing 32 of 244 vendor product statements; 212 omitted. Read the full vendor advisory.

  • curl-debuginfo-0:8.12.1-1.el10_0.10.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0.10?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-minimal-debuginfo-0:8.12.1-1.el10_0.10.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0.10?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-devel-0:8.12.1-4.el10_2.6.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.6?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl-debugsource-0:7.76.1-40.el9_8.8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.8?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-minimal-debuginfo-0:7.76.1-40.el9_8.8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.8?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl-debugsource-0:8.12.1-1.el10_0.10.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0.10?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-minimal-debuginfo-0:8.12.1-1.el10_0.10.s390x as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0.10?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-0:8.12.1-4.el10_2.6.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.6?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl-0:7.76.1-40.el9_8.8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.8?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl-minimal-0:7.76.1-40.el9_8.8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.8?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-debuginfo-0:7.76.1-40.el9_8.8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.8?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl-0:8.21.0-0.1.hum1@src as a component of Red Hat Hardened Images · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]?arch=src&distro=hummingbird-20251124&repository_id=public-hummingbird-source-rpms

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/ Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • rust-doc-0:1.96.1-1.hum1@x86_64 as a component of Red Hat Hardened Images · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]?arch=x86_64&distro=hummingbird-20251124&repository_id=public-hummingbird-x86_64-rpms

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/ Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • rust-std-static-wasm32-unknown-unknown-0:1.96.1-1.hum1@noarch@public-hummingbird-x86_64-rpms as a component of Red Hat Hardened Images · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]?arch=noarch&distro=hummingbird-20251124&repository_id=public-hummingbird-x86_64-rpms

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/ Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • registry.redhat.io/rhui5/rhua-rhel9@sha256:fa09f523d2501e42f9c78c18bd99475f562e7397ed75d8c0fc8e183bcbf4c827_amd64 as a component of Red Hat Update Infrastructure 5 · fixed

    Vendor assessment for this product only.

    pkg:oci/rhua-rhel9@sha256%3Afa09f523d2501e42f9c78c18bd99475f562e7397ed75d8c0fc8e183bcbf4c827?arch=amd64&repository_url=registry.redhat.io/rhui5/rhua-rhel9&tag=1791978693

    • vendor fix: The container images provided by this release, apart from the installer, should be deployed using rhui-installer utility. See the official documentation for more details. Vendor guidance
    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl.src as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl?arch=src

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-devel as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl-devel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl as a component of Red Hat Enterprise Linux 7 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl.src as a component of Red Hat Enterprise Linux 7 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl?arch=src

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl as a component of Red Hat Enterprise Linux 7 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-devel as a component of Red Hat Enterprise Linux 7 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl-devel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • no fix planned: Out of support scope
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Affected
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • curl.src as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/curl?arch=src

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Affected
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Affected
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-devel as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl-devel

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Affected
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • libcurl-minimal as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libcurl-minimal

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Affected
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4 · known affected

    Vendor assessment for this product only.

    pkg:oci/ose-rhel-coreos-8?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-8

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Fix deferred
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known affected

    Vendor assessment for this product only.

    pkg:oci/ose-rhel-coreos-9?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-9

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Correct usage of the library: Create a fresh handle for a different origin, or explicitly clear authentication-related state before reuse: ```c // req.A curl = curl_easy_init(); ... curl_easy_cleanup(curl); // req.B curl = curl_easy_init(); ... curl_easy_cleanup(curl); ``` Fixed in libcurl 8.21.0; affected range: 7.10.6 – 8.20.0
    • none available: Fix deferred
    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • devspaces/code-rhel9 as a component of Red Hat OpenShift Dev Spaces · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/code-rhel9?repository_url=registry.redhat.io/devspaces/code-rhel9

    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00
  • rhtpa/rhtpa-trustification-service-rhel9 as a component of Red Hat Trusted Profile Analyzer · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/rhtpa-trustification-service-rhel9?repository_url=registry.redhat.io/rhtpa/rhtpa-trustification-service-rhel9

    Red Hat · CVE-2026-11856 · Updated 2026-10-14T19:15:04+00:00

Known Affected Software Configurations

VendorProductVersion range
HaxxCurl≥ 7.10.6 and < 8.21.0

All CVSS metrics

  • CRITICAL 9.8 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS