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.
History

Wed, 27 May 2026 10:30:00 +0000

Type Values Removed Values Added
First Time appeared Gnu
Gnu gnutls
Redhat hardened Images
Redhat openshift Container Platform
Vendors & Products Gnu
Gnu gnutls
Redhat hardened Images
Redhat openshift Container Platform

Wed, 27 May 2026 03:30:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/o:redhat:enterprise_linux:8::baseos
References

Tue, 26 May 2026 21:45:00 +0000

Type Values Removed Values Added
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.
Title Gnutls: gnutls: certificate validation bypass due to oversized subject alternative name
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-1284
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published: 2026-05-26T21:29:32.887Z

Updated: 2026-05-27T02:18:04.024Z

Reserved: 2026-04-23T11:23:46.517Z

Link: CVE-2026-42013

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-26T22:16:42.050

Modified: 2026-05-27T14:54:20.160

Link: CVE-2026-42013

cve-icon Redhat

No data.