What’s Vulnerable › Vulnerabilities
CVE-2026-6731: X.509 name constraint bypass via Subject CN treated as a DNS name
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-25 · updated 2026-06-27
- Weakness: CWE-295
Description
X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted.
Affected products
- wolfSSL: from 3.9.10 before 5.9.2 — fixed in 5.9.2
How to fix
Upgrade to a fixed version: wolfSSL 5.9.2. Check the vendor advisory for mitigations.
References
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