# CVE-2026-42013

## Summary

- **CVE ID:** CVE-2026-42013
- **Severity:** HIGH
- **CVSS Score:** 8.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N)
- **CWE:** CWE-1284, CWE-295
- **Published:** May 26, 2026
- **Last Modified:** Sep 14, 2026

## 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.

## Affected Products

- Unknown product (0)
- Red Hat — Red Hat Enterprise Linux 8 (0:3.6.16-8.el8_10.6)
- Red Hat — Red Hat Enterprise Linux 10 (0:3.8.10-4.el10_2)
- Red Hat — Red Hat Enterprise Linux 9 (0:3.8.10-4.el9_8)
- Red Hat — Red Hat Enterprise Linux 10.0 Extended Update Support (0:3.8.9-9.el10_0.19)
- Red Hat — Red Hat Update Infrastructure 5 (1781525684)
- Red Hat — Red Hat Update Infrastructure 5 (1781525671)
- Red Hat — Red Hat Update Infrastructure 5 (1781525693)
- Red Hat — Red Hat Update Infrastructure 5 (1781525739)
- Red Hat — Red Hat Discovery 2 (1782159791)
- Red Hat — Red Hat Discovery 2 (1782166952)
- Red Hat — Red Hat Enterprise Linux 9.6 Extended Update Support (0:3.8.3-6.el9_6.4)
- Red Hat — Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (0:3.6.14-10.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (0:4.13-3.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (0:3.6.14-10.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (0:4.13-3.el8_4.1)
- Red Hat — Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (0:3.6.16-5.el8_6.5)
- Red Hat — Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (0:4.13-3.el8_6.2)
- Red Hat — Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (0:3.6.16-5.el8_6.5)
- Red Hat — Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (0:4.13-3.el8_6.2)
- Red Hat — Red Hat Enterprise Linux 8.8 Telecommunications Update Service (0:3.6.16-7.el8_8.4)
- Red Hat — Red Hat Enterprise Linux 8.8 Telecommunications Update Service (0:4.13-4.el8_8.1)
- Red Hat — Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (0:3.6.16-7.el8_8.4)
- Red Hat — Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (0:4.13-4.el8_8.1)
- Red Hat — Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (0:3.8.3-4.el9_4.6)
- Red Hat — Red Hat Hardened Images (3.8.13-1.hum1)
- Red Hat — Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (0:3.7.6-21.el9_2.7)
- Red Hat — Red Hat Enterprise Linux 7 Extended Lifecycle Support (0:3.3.29-9.el7_9.2)
- Red Hat — Red Hat OpenShift Container Platform 4.19 (4.19.9.6.202607151909-0)
- Red Hat — Red Hat Update Infrastructure 5 (1787241211)
- Red Hat — Red Hat Update Infrastructure 5 (1787135742)
- Red Hat — Red Hat Update Infrastructure 5 (1787241260)
- Red Hat — Red Hat OpenShift Container Platform 4.18 (418.94.202608142238-0)
- Red Hat — Red Hat OpenShift Container Platform 4.16 (416.94.202608150307-0)
- Red Hat — Red Hat OpenShift Container Platform 4.12 (412.86.202608241157-0)
- Red Hat — Red Hat OpenShift Container Platform 4.17 (417.94.202608250221-0)

## References

- [CNA](https://access.redhat.com/security/cve/CVE-2026-42013)
- [CNA](https://bugzilla.redhat.com/show_bug.cgi?id=2467448)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20611)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20613)
- [CNA](https://access.redhat.com/errata/RHSA-2026:20612)
- [CNA](https://access.redhat.com/errata/RHSA-2026:26319)
- [CNA](https://access.redhat.com/errata/RHSA-2026:26409)
- [CNA](https://access.redhat.com/errata/RHSA-2026:29197)
- [CNA](https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-8)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30004)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30849)
- [CNA](https://access.redhat.com/errata/RHSA-2026:30850)
- [CNA](https://access.redhat.com/errata/RHSA-2026:32962)
- [CNA](https://access.redhat.com/errata/RHSA-2026:33125)
- [CNA](https://access.redhat.com/errata/RHSA-2026:13274)
- [CNA](https://access.redhat.com/errata/RHSA-2026:41921)
- [CNA](https://access.redhat.com/errata/RHSA-2026:40762)
- [CNA](https://access.redhat.com/errata/RHSA-2026:43575)
- [CNA](https://access.redhat.com/errata/RHSA-2026:58981)
- [CNA](https://access.redhat.com/errata/RHSA-2026:57483)
- [CNA](https://access.redhat.com/errata/RHSA-2026:56853)
- [CNA](https://access.redhat.com/errata/RHSA-2026:59831)
- [CNA](https://access.redhat.com/errata/RHSA-2026:60019)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.42%
- **EPSS Percentile:** 36.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._