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CVE-2026-4271

MEDIUM 5.3 ALL-YEARS

Published 2026-03-17 · Last modified 2026-05-19 · redhat · NVD: Modified

A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS).

LIMITED SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.9%chance of exploitation in 30 days · 58th percentile

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

Impact if exploited

5.3CVSS 3.1 · MEDIUM · CNA

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityLow

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 Red Hat Gnome Redhat

Products Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Libsoup Enterprise Linux

Weakness (CWE)

  • CWE-416: Use After Free

CVSS vector

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

References and research data (JSON)

Vendor product assessments

Showing 32 of 66 vendor product statements; 34 omitted. Read the full vendor advisory.

  • libsoup3-0:3.6.5-3.el10_0.15.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]_0.15?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-0:3.6.5-3.el10_0.15.src 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]_0.15?arch=src

    • 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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_0.15.ppc64le 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]_0.15?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_0.15.x86_64 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]_0.15?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debugsource-0:3.6.5-3.el10_0.15.s390x 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]_0.15?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-devel-0:3.6.5-3.el10_0.15.ppc64le 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]_0.15?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-0:3.6.5-3.el10_1.11.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-0:3.6.5-3.el10_1.11.src as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?arch=src

    • 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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_1.11.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_1.11.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debugsource-0:3.6.5-3.el10_1.11.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-devel-0:3.6.5-3.el10_1.11.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-devel-0:3.6.5-3.el10_1.11.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_1.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-0:3.6.5-3.el10_2.11.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_2.11.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debuginfo-0:3.6.5-3.el10_2.11.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-debugsource-0:3.6.5-3.el10_2.11.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-devel-0:3.6.5-3.el10_2.11.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-devel-0:3.6.5-3.el10_2.11.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup3-doc-0:3.6.5-3.el10_2.11.noarch as a component of Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.11?arch=noarch

    • 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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libsoup

    • workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    • no fix planned: Will not fix
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup-devel as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libsoup-devel

    • workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    • no fix planned: Will not fix
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup.src as a component of Red Hat Enterprise Linux 6 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/libsoup?arch=src

    • workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
    • no fix planned: Will not fix
    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup-devel

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup.src as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup?arch=src

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup-devel as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup-devel

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup.src as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup?arch=src

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup-devel as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup-devel

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00
  • libsoup.src as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/libsoup?arch=src

    Red Hat · CVE-2026-4271 · Updated 2026-08-18T12:08:16+00:00

Known Affected Software Configurations

VendorProductVersion range
GnomeLibsoup*
RedhatEnterprise Linux6.0
RedhatEnterprise Linux7.0
RedhatEnterprise Linux8.0
RedhatEnterprise Linux9.0
RedhatEnterprise Linux10.0

All CVSS metrics

  • MEDIUM 5.3 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
  • MEDIUM 5.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
  • HIGH 7.5 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Exploit-tagged references (not proof of a PoC)

Advisories

Technical & other

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