CVE-2026-67693: Gnutls26 · GnuTLS v3.8.13 does not reject end-entity X.509 certificates that contain a contradictory
Affects gnutls26Source GCVE Database
Not known to be exploited · CVSS 3.7 Low.
Data as of 5 Nov 2026, 12:34 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 3.7 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 8 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10gnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSgnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSgnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro FIPS-updates 24.04 LTSgnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=fips-updates/nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSgnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro FIPS-preview 22.04 LTSgnutls28pkg:deb/ubuntu/gnutls28?arch=source&distro=fips-preview/jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
GnuTLS v3.8.13 does not reject end-entity X.509 certificates that contain a contradictory combination of Key Usage (KU) and Extended Key Usage (EKU). NOTE: the Supplier does not consider this an actionable security vulnerability because of its "threat model doesn't consider attacks only possible by modifying anything within the trust boundary (private keys, trusted certificate authorities and their issued certificates including intermediate CAs, etc.)" policy.