CVE-2026-42013
HIGHCVSS 8.2/10EPSS 0.42%
Last modified
CVE-2026-42013 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. 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. EPSS estimates a 0.42% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | All versions |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8 | All versions |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | All versions |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | All versions |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9 | All versions |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | All versions |
| Red Hat | Red Hat OpenShift Container Platform 4.19 | All versions |
| Red Hat | Red Hat Discovery 2 | All versions |
| Red Hat | Red Hat Hardened Images | All versions |
| Red Hat | Red Hat Update Infrastructure 5 | All versions |
| Red Hat | Red Hat Enterprise Linux 6 | All versions |
| Red Hat | Red Hat OpenShift Container Platform 4 | All versions |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-42013?
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.
How severe is CVE-2026-42013?
CVE-2026-42013 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.
How do I fix CVE-2026-42013?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-42013?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST