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CVE-2026-3833

MEDIUM 6.5 ALL-YEARS

Published 2026-04-30 · Last modified 2026-10-14 · redhat · NVD: Modified

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

LIMITED SIGNALS

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

Exploitation likelihood

0.6%chance of exploitation in 30 days · 47th percentile

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

Impact if exploited

6.5CVSS 3.1 · MEDIUM · CNA

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

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 Gnu Redhat

Products Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat Enterprise Linux 7 Extended Lifecycle Support Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long Life Add On Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.6 Extended Update Support Long Life Add On Red Hat Enterprise Linux 8.8 Telecommunications Update Service Red Hat Enterprise Linux 8.8 Update Services For Sap Solutions Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 9.2 Update Services For Sap Solutions Red Hat Enterprise Linux 9.4 Update Services For Sap Solutions Red Hat Enterprise Linux 9.6 Extended Update Support Red Hat Openshift Container Platform 4.12 Red Hat Openshift Container Platform 4.13 Red Hat Openshift Container Platform 4.14 Red Hat Openshift Container Platform 4.15 Red Hat Openshift Container Platform 4.16 Red Hat Openshift Container Platform 4.17 Red Hat Openshift Container Platform 4.18 Red Hat Openshift Container Platform 4.19 Cert Manager Support For Red Hat Openshift Release 1.17 Cert Manager Support For Red Hat Openshift Release 1.18 Cert Manager Support For Red Hat Openshift Release 1.20 Red Hat Discovery 2 Red Hat Hardened Images Red Hat Openshift Ai 3.4 Red Hat Update Infrastructure 5 Red Hat Enterprise Linux 6 Red Hat Openshift Container Platform 4 Gnutls Hardened Images Openshift Container Platform Enterprise Linux

Weakness (CWE)

  • CWE-178: Improper Handling of Case Sensitivity

CVSS vector

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

References and research data (JSON)

Vendor product assessments

Showing 32 of 954 vendor product statements; 922 omitted. Read the full vendor advisory.

  • gnutls-0:3.3.29-9.el7_9.2.i686 as a component of Red Hat Enterprise Linux Server (v. 7 ELS) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_9.2?arch=i686

    • 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-0:3.8.9-9.el10_0.19.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_0.19?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-debugsource-0:3.8.10-4.el10_2.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?arch=x86_64

    • vendor fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.6.16-8.el8_10.6.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10.6?arch=s390x

    • vendor fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-debugsource-0:3.6.16-5.el8_6.5.x86_64 as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_6.5?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.6.16-7.el8_8.4.i686 as a component of Red Hat Enterprise Linux AppStream E4S (v.8.8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.4?arch=i686

    • 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-dane-debuginfo-0:3.7.6-21.el9_2.7.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2.7?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-devel-0:3.8.3-4.el9_4.6.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_4.6?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-dane-0:3.8.10-4.el9_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?arch=s390x

    • vendor fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.8.10-4.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_2?arch=s390x

    • vendor fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-debugsource-0:3.6.14-10.el8_4.1.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_4.1?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.6.16-5.el8_6.5.i686 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_6.5?arch=i686

    • 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • libtasn1-tools-debuginfo-0:4.13-4.el8_8.1.x86_64 as a component of Red Hat Enterprise Linux BaseOS TUS (v.8.8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8.1?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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.8.3-4.el9_4.6.i686 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_4.6?arch=i686

    • 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • registry.redhat.io/cert-manager/cert-manager-operator-rhel9@sha256:bc5b798da5bb23a48f26b3592e39e4f1449bf6f279fe47741b5cda43a0923085_amd64 as a component of Cert Manager support for Red Hat OpenShift release 1.17 · fixed

    Vendor assessment for this product only.

    pkg:oci/cert-manager-operator-rhel9@sha256%3Abc5b798da5bb23a48f26b3592e39e4f1449bf6f279fe47741b5cda43a0923085?arch=amd64&repository_url=registry.redhat.io/cert-manager/cert-manager-operator-rhel9&tag=1791788287

    • vendor fix: Before applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If the approval policy is set to `Automatic`, then the Operator will be upgraded automatically when there is a new version of the Operator. No further action is required to upgrade. This is the default setting. - If you changed the approval policy to `Manual`, then you must manually approve the upgrade to the Operator. See https://docs.openshift.com/container-platform/latest/security/cert_manager_operator/index.html for additional information. 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • registry.redhat.io/rhui5/rhua-tp-rhel9@sha256:2dc99bbbcad15bd50b1ad227f6d4557f5b17fed7388e3eb127c058e3f4636b15_amd64 as a component of Red Hat Update Infrastructure 5 · fixed

    Vendor assessment for this product only.

    pkg:oci/rhua-tp-rhel9@sha256%3A2dc99bbbcad15bd50b1ad227f6d4557f5b17fed7388e3eb127c058e3f4636b15?arch=amd64&repository_url=registry.redhat.io/rhui5/rhua-tp-rhel9&tag=1787241260

    • vendor fix: Please consult the RHUI Technology Preview Release Notes at https://access.redhat.com/articles/7141172 for instructions on how to use this image set. 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.
    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-debuginfo-0:3.3.29-9.el7_9.2.i686 as a component of Red Hat Enterprise Linux Server (v. 7 ELS) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_9.2?arch=i686

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-debuginfo-0:3.3.29-9.el7_9.2.s390x as a component of Red Hat Enterprise Linux Server (v. 7 ELS) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_9.2?arch=s390x

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.8.9-9.el10_0.19.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_0.19?arch=x86_64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.6.14-10.el8_4.1.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_4.1?arch=x86_64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.6.16-7.el8_8.4.i686 as a component of Red Hat Enterprise Linux AppStream E4S (v.8.8) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_8.4?arch=i686

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.8.3-6.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_6.4?arch=aarch64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-dane-debuginfo-0:3.8.3-6.el9_6.4.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_6.4?arch=aarch64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.8.9-9.el10_0.19.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_0.19?arch=aarch64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-utils-debuginfo-0:3.6.14-10.el8_4.1.i686 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_4.1?arch=i686

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-dane-debuginfo-0:3.6.16-5.el8_6.5.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.6) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_6.5?arch=x86_64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.6.16-7.el8_8.4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.8.8) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_8.4?arch=x86_64

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-c++-debuginfo-0:3.8.3-6.el9_6.4.ppc64le as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls-c%2B%[email protected]_6.4?arch=ppc64le

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls-dane-debuginfo-0:3.8.3-6.el9_6.4.i686 as a component of Red Hat Enterprise Linux BaseOS EUS (v.9.6) · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]_6.4?arch=i686

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • registry.redhat.io/rhui5/cds-tp-rhel9@sha256:9160d973640e48fd9d72f92f5395f2d61f54fa2dae7dce4e6658dfc420f53088_amd64 as a component of Red Hat Update Infrastructure 5 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/cds-tp-rhel9@sha256%3A9160d973640e48fd9d72f92f5395f2d61f54fa2dae7dce4e6658dfc420f53088?arch=amd64&repository_url=registry.redhat.io/rhui5/cds-tp-rhel9&tag=1787241206

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • gnutls.src as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/gnutls?arch=src

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00
  • openshift4/ose-hypershift-rhel9 as a component of Red Hat OpenShift Container Platform 4 · under investigation

    Vendor assessment for this product only.

    pkg:oci/ose-hypershift-rhel9?repository_url=registry.redhat.io/openshift4/ose-hypershift-rhel9

    Red Hat · CVE-2026-3833 · Updated 2026-10-14T19:24:09+00:00

Known Affected Software Configurations

VendorProductVersion range
GnuGnutls*
RedhatHardened Images*
RedhatOpenshift Container Platform4.0
RedhatEnterprise Linux6.0
RedhatEnterprise Linux7.0
RedhatEnterprise Linux8.0
RedhatEnterprise Linux9.0
RedhatEnterprise Linux10.0

All CVSS metrics

  • MEDIUM 6.5 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
  • MEDIUM 6.5 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
  • HIGH 7.4 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Exploit-tagged references (not proof of a PoC)

Advisories

Technical & other

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