Red Hat Security Advisory: gnutls security update

Fixed packages 5

Vulnerabilities 3

• High 7.5
  CVE-2026-33845

  Gnutls: gnutls: denial of service via dtls zero-length fragment

  A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information dis…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  Apr 30, 2026
• High 7.5
  CVE-2026-33846

  Gnutls: gnutls: denial of service via heap buffer overflow in dtls handshake fragment reassembly

  A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating th…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  May 4, 2026
• High 7.5
  CVE-2026-42009

  Gnutls: gnutls: denial of service via dtls packet reordering vulnerability

  A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux Alpine
  May 18, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#important
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2450624
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2450625
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2467279
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_34372.json
• report
  https://access.redhat.com/security/cve/CVE-2026-33845
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-33845
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-33845
• report
  https://access.redhat.com/security/cve/CVE-2026-33846
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-33846
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-33846
• report
  https://access.redhat.com/security/cve/CVE-2026-42009
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-42009
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-42009
• article
  https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-2