CVE-2026-42013: gnutls · CWE-1284
Affects gnutlsSource GCVE Database
Not known to be exploited · CVSS 8.2 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 26 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Red Hatredhat/gnutlspkg:rpm/redhat/gnutlsOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official security update is available from Red Hat as part of RHSA-2026:43575, which fixes this vulnerability in GnuTLS version 3.3.29-9.el7_9.2. Users should apply this update to affected systems. Refer to Red Hat's advisory and article https://access.redhat.com/articles/11258 for detailed patching instructions.
Description
CVE-2026-42013 is a vulnerability in the GnuTLS library where an oversized Subject Alternative Name (SAN) in a certificate causes the validation process to incorrectly fall back to checking the Common Name (CN) field. This flaw can allow remote attackers to bypass proper certificate validation, potentially enabling spoofing or man-in-the-middle attacks. The issue affects certain versions of GnuTLS in Red Hat Enterprise Linux 7 Extended Lifecycle Support. Red Hat has released an official security update that addresses this vulnerability.
References
- nvd.nist.gov/vuln/detail/CVE-2026-42013 (opens in a new tab)
- gnutls.org/security-new.html (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2467448 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-42013 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:43575 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41921 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:40762 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:33125 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:32962 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30850 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30849 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30004 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:29197 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26409 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26319 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20613 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20612 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20611 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:13274 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:58981 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:56853 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:57483 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59831 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:72502 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:60019 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:74674 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82304 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82322 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82347 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82354 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82372 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82857 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82888 (opens in a new tab)