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CVE-2026-42013

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

Published: May 26, 2026Updated: Sep 3, 2026 Sources: CVE List NVDCWE-295
8.2HIGH
NVD MITRE
EPSS Score
0.6%
Top 55.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-295

Affected Products

Red Hat
commercial·US
Red Hat Enterprise Linux 10On-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 10.0 Extended Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 7 Extended Lifecycle SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnOn-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceOn-premOS
Operating Systems / linux-distro
and 17 more affected products View all →

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://access.redhat.com/errata/RHSA-2026:13274
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20611
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20612
access.redhat.com
and 20 more references View all →

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