CVE-2026-42013
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | fixed | 3.7.9-2+deb12u7 |
| debian | bullseye | fixed | 3.7.1-5+deb11u10 |
| debian | forky | fixed | 3.8.13-1 |
| debian | sid | fixed | 3.8.13-1 |
| debian | trixie | fixed | 3.8.9-3+deb13u4 |
| sles | affected | |
References
- https://access.redhat.com/errata/RHSA-2026:20611
- https://access.redhat.com/security/cve/CVE-2026-42013
- https://bugzilla.redhat.com/show_bug.cgi?id=2467448
- https://security-tracker.debian.org/tracker/CVE-2026-42013
- https://www.suse.com/security/cve/CVE-2026-42013.html
- https://bugzilla.redhat.com/2445763
- https://bugzilla.redhat.com/2450624
- https://bugzilla.redhat.com/2450625
- https://bugzilla.redhat.com/2467279
- https://bugzilla.redhat.com/2467289
- https://bugzilla.redhat.com/2467437
- https://errata.almalinux.org/8/ALSA-2026-20611.html
CWEs
CWE-1284
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.