CVE-2026-42013
HIGHGnutls: gnutls: certificate validation bypass due to oversized subject alternative name
Title source: cnaDescription
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.
References (5)
Core 5
Core References
Vendor Advisory vendor-advisory
x_refsource_redhat
RHSA-2026:20612
https://access.redhat.com/errata/RHSA-2026:20612
Vendor Advisory vendor-advisory
x_refsource_redhat
https://access.redhat.com/errata/RHSA-2026:20613
Vendor Advisory vendor-advisory
x_refsource_redhat
RHSA-2026:20611
https://access.redhat.com/errata/RHSA-2026:20611
Vdb Entry, X_Refsource_Redhat vdb-entry
x_refsource_redhat
https://access.redhat.com/security/cve/CVE-2026-42013
Issue Tracking, X_Refsource_Redhat issue-tracking
x_refsource_redhat
RHBZ#2467448
https://bugzilla.redhat.com/show_bug.cgi?id=2467448
Scores
CVSS v3
8.2
EPSS
0.0036
EPSS Percentile
27.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-1284
Status
published
Products (10)
Red Hat/Red Hat Enterprise Linux 10
Red Hat/Red Hat Enterprise Linux 10
0:3.8.10-4.el10_2
Red Hat/Red Hat Enterprise Linux 6
Red Hat/Red Hat Enterprise Linux 7
Red Hat/Red Hat Enterprise Linux 8
Red Hat/Red Hat Enterprise Linux 8
0:3.6.16-8.el8_10.6
Red Hat/Red Hat Enterprise Linux 9
Red Hat/Red Hat Enterprise Linux 9
0:3.8.10-4.el9_8
Red Hat/Red Hat Hardened Images
Red Hat/Red Hat OpenShift Container Platform 4
Published
May 26, 2026
Tracked Since
May 27, 2026