Quick answers
- Is CVE-2026-95210 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-95210 being exploited in the wild.
- How severe is CVE-2026-95210?
- Medium severity, with a CVSS score of 4.8, published 8 October 2026.
- Which products and versions are affected?
- GnuTLS 3.8.13.
- Is there a fix for CVE-2026-95210?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-95210 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-95210?
- Check whether you run GnuTLS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
GnuTLS's path validation performs a critical-extension check using only OID matching (is_ext_oid_supported()) without parsing the extension value itself. When an end-entity certificate carries a critical keyUsage extension with a malformed value (e.g., DER-encoded NULL instead of BIT STRING), the validation gate passes because the OID is recognized. However, the actual extension value is never parsed during verification, only during lazy accessor calls that may never occur on the end-entity certificate. This creates a gap where gnutls_x509_ext_import_key_usage() would reject the malformed value but is never invoked, violating RFC 5280's requirement to reject critical extensions that cannot be processed.
Affected products
- GnuTLS GnuTLS 3.8.13
Timeline
- 2026-10-08: disclosed