CVE-2026-42013

Gnutls: gnutls: certificate validation bypass due to oversized subject alternative name

HIGH
8.2
CVSS Score
Published: May 26, 2026 at 09:29 PM UTC
Updated: October 29, 2026 at 06:17 AM UTC
2 products affected across 1 vendorEnterprise LinuxOpenShift Container Platform

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Severity
HIGH8.2
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.

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 (unknown)
All versions4
Vendor states this is fixed in 4.19.9.6.202607151909-0 (unaffected)
Vendor states this is fixed in 412.86.202608241157-0 (unaffected)
Vendor states this is fixed in 416.94.202608150307-0 (unaffected)
Vendor states this is fixed in 417.94.202608250221-0 (unaffected)
Vendor states this is fixed in 418.94.202608142238-0 (unaffected)
Vendor states this is fixed in 4 (unknown)

References (35)

VDB Entryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-42013
Issue Trackingx_refsource_REDHAT
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2467448
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
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:26409
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:29197

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

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

CVSS

8.2HIGHredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-1284CWE-295

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