CVE-2026-42013: Improper Certificate Validation
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.
CVE-2026-42013: Improper Certificate Validation
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.
CVSS v3.1
Score 8.2high
Affected software
Red Hat
Red Hat Enterprise Linux 10
Red Hat
Red Hat Enterprise Linux 10.0 Extended Update Support
Red Hat
Red Hat Enterprise Linux 7 Extended Lifecycle Support
Red Hat
Red Hat Enterprise Linux 8
Red Hat
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
Red Hat
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
Red Hat
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
Red Hat
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
Red Hat
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
Red Hat
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
Red Hat
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
Red Hat
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
Red Hat
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
Red Hat
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
Red Hat
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
Red Hat
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
Red Hat
Red Hat Enterprise Linux 9
Red Hat
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
Red Hat
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
Red Hat
Red Hat Enterprise Linux 9.6 Extended Update Support
Red Hat
Red Hat OpenShift Container Platform 4.12
Red Hat
Red Hat OpenShift Container Platform 4.16
Red Hat
Red Hat OpenShift Container Platform 4.17
Red Hat
Red Hat OpenShift Container Platform 4.18
Red Hat
Red Hat OpenShift Container Platform 4.19
Red Hat
Red Hat Discovery 2
Red Hat
Red Hat Discovery 2
Red Hat
Red Hat Hardened Images
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Update Infrastructure 5
Red Hat
Red Hat Enterprise Linux 6
Red Hat
Red Hat OpenShift Container Platform 4
Red Hat
Red Hat OpenShift Container Platform 4
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-04-23T11:23:46.517Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-42013","vendor":"Red Hat"}]
Threat ID: 6a161534e29bf47b506c5220
Added to database: 05/26/2026, 21:48:36 UTC
Last enriched: 07/21/2026, 18:23:11 UTC
Last updated: 09/13/2026, 10:01:30 UTC
Views: 110
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