CVE-2026-42012

Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans

At a glance

Severity: HIGH 7.1
EPSS: EPSS 0.35 % · percentile 29 (2026-10-27)
State: PUBLISHED
Published: 2026-05-26
Updated: 2026-10-14
Assigner: redhat
NVD status: Awaiting Analysis

Description

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N	redhat
CVSS 3.1	HIGH 7.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N	NVD · secalert@redhat.com (Secondary)

Weaknesses (CWE)

CWE-295

European references

ENISA EUVD · EUVD-2026-32010
GCVE · GCVE-0-2026-42012

CERT-FR advisories

CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-0737 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr

Affected products

Product	Versions
gnutls	affected 0
Red Hat · Red Hat Enterprise Linux 10	unaffected 0:3.8.10-4.el10_2 < *
Red Hat · Red Hat Enterprise Linux 10.0 Extended Update Support	unaffected 0:3.8.9-9.el10_0.19 < *
Red Hat · Red Hat Enterprise Linux 7 Extended Lifecycle Support	unaffected 0:3.3.29-9.el7_9.2 < *
Red Hat · Red Hat Enterprise Linux 8	unaffected 0:3.6.16-8.el8_10.6 < *
Red Hat · Red Hat Enterprise Linux 8	unaffected 0:3.6.16-8.el8_10.6 < *
Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	unaffected 0:3.6.14-10.el8_4.1 < *
Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	unaffected 0:4.13-3.el8_4.1 < *
Red Hat · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	unaffected 0:3.6.14-10.el8_4.1 < *
Red Hat · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	unaffected 0:4.13-3.el8_4.1 < *
Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	unaffected 0:3.6.16-5.el8_6.5 < *
Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	unaffected 0:4.13-3.el8_6.2 < *
Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	unaffected 0:3.6.16-5.el8_6.5 < *
Red Hat · Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	unaffected 0:4.13-3.el8_6.2 < *
Red Hat · Red Hat Enterprise Linux 8.8 Telecommunications Update Service	unaffected 0:3.6.16-7.el8_8.4 < *
Red Hat · Red Hat Enterprise Linux 8.8 Telecommunications Update Service	unaffected 0:4.13-4.el8_8.1 < *
Red Hat · Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	unaffected 0:3.6.16-7.el8_8.4 < *
Red Hat · Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	unaffected 0:4.13-4.el8_8.1 < *
Red Hat · Red Hat Enterprise Linux 9	unaffected 0:3.8.10-4.el9_8 < *
Red Hat · Red Hat Enterprise Linux 9	unaffected 0:3.8.10-4.el9_8 < *

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD