CVE-2026-3833

Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

HIGH
7.4
CVSS Score
Published: April 30, 2026 at 05:37 PM UTC
Updated: October 14, 2026 at 08:17 PM UTC
4 products affected across 2 vendorsEnterprise LinuxOpenShift Container PlatformHardened Images

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Severity
HIGH7.4
Exploit prediction
EPSS 0.6%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions
Vendor states this is fixed in 0:3.3.29-9.el7_9.2 (unaffected)
Vendor states this is fixed in 0:3.6.14-10.el8_4.1 (unaffected)
Vendor states this is fixed in 0:3.6.16-5.el8_6.5 (unaffected)
Vendor states this is fixed in 0:3.6.16-7.el8_8.4 (unaffected)
Vendor states this is fixed in 0:3.6.16-8.el8_10.6 (unaffected)
Vendor states this is fixed in 0:3.7.6-21.el9_2.7 (unaffected)
Vendor states this is fixed in 0:3.8.10-4.el10_2 (unaffected)
Vendor states this is fixed in 0:3.8.10-4.el9_8 (unaffected)
Vendor states this is fixed in 0:3.8.3-4.el9_4.6 (unaffected)
Vendor states this is fixed in 0:3.8.3-6.el9_6.4 (unaffected)
Vendor states this is fixed in 0:3.8.9-9.el10_0.19 (unaffected)
Vendor states this is fixed in 0:4.13-3.el8_4.1 (unaffected)
Vendor states this is fixed in 0:4.13-3.el8_6.2 (unaffected)
Vendor states this is fixed in 0:4.13-4.el8_8.1 (unaffected)
Vendor states this is fixed in 6 (unaffected)
All versions1
Vendor states this is fixed in 3.8.13-1.hum1 (unaffected)
Vendor states this is fixed in 4.19.9.6.202608182320-0 (unaffected)
Vendor states this is fixed in 412.86.202608241157-0 (unaffected)
Vendor states this is fixed in 413.92.202609080414-0 (unaffected)
Vendor states this is fixed in 414.92.202609011250-0 (unaffected)
Vendor states this is fixed in 415.92.202609140326-0 (unaffected)
Vendor states this is fixed in 416.94.202609011112-0 (unaffected)
Vendor states this is fixed in 417.94.202608250221-0 (unaffected)
Vendor states this is fixed in 418.94.202609031320-0 (unaffected)
Vendor states this is fixed in 4 (unknown)

References (35)

VDB Entryx_refsource_REDHATThird Party Advisory
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-3833
Issue Trackingx_refsource_REDHATThird Party Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2445763
ExploitIssue TrackingVendor Advisory
Source: cverecord
https://gitlab.com/gnutls/gnutls/-/issues/1803
Vendor Advisoryx_refsource_REDHATIssue TrackingThird Party Advisory
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:13274
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:20611
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:20613
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:20612
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:26319

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-178

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