Red Hat Security Advisory: gnutls security update

Fixed packages 5

Vulnerabilities 6

• High 8.2
  CVE-2026-42013

  Gnutls: gnutls: certificate validation bypass due to oversized subject alternative name

  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 certi…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  May 26, 2026
• High 7.4
  CVE-2026-42011

  Gnutls: gnutls: security bypass due to incorrect name constraint handling

  A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name cons…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Alpine
  May 7, 2026
• High 7.1
  CVE-2026-42012

  Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans

  A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate va…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 10 Linux Debian Ubuntu Azure Linux Alpine
  May 26, 2026
• Medium 6.6
  CVE-2026-42014

  Gnutls: gnutls: use-after-free in gnutls_pkcs11_token_set_pin

  A flaw was found in GnuTLS. The `gnutls_pkcs11_token_set_pin` function, used for changing the Security Officer PIN, can lead to a use-after-free vulnerability. This occurs when an attacker attempts to change the PIN with a NULL old PIN for a token that lacks …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Jun 16, 2026
• Medium 6.5
  CVE-2026-3833

  Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

  A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remo…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Alpine
  Apr 30, 2026
• Medium 5.3
  CVE-2026-42015

  Gnutls: gnutls: memory corruption due to off-by-one error in pkcs#12 bag handling

  A flaw was found in gnutls. An off-by-one error exists in the PKCS#12 bag element bounds check. This vulnerability allows an remote attacker to write past the internal array of a PKCS#12 bag when appending to a bag that already contains 32 elements. This memo…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  May 26, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#moderate
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2445763
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467437
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467441
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467448
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467451
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467678
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_43575.json
• report
  https://access.redhat.com/security/cve/CVE-2026-3833
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-3833
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-3833
• article
  https://gitlab.com/gnutls/gnutls/-/issues/1803
• report
  https://access.redhat.com/security/cve/CVE-2026-42011
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42011
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42011
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-6
• report
  https://access.redhat.com/security/cve/CVE-2026-42012
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42012
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42012
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-7
• report
  https://access.redhat.com/security/cve/CVE-2026-42013
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42013
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42013
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-8
• report
  https://access.redhat.com/security/cve/CVE-2026-42014
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42014
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42014
• article
  https://gitlab.com/gnutls/gnutls/-/issues/1766
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-9
• report
  https://access.redhat.com/security/cve/CVE-2026-42015
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42015
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42015
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-11