CVE-2026-42009

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 with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.

This vulnerability is rated as an Important impact because an unauthenticated remote attacker can cause a denial of service without requiring user interaction or elevated privileges. The defect specifically resides in the datagram reordering logic of GnuTLS, leaving standard TCP-based TLS services unaffected across Red Hat environments. Systems are only exposed if they run network services configured to process untrusted Datagram Transport Layer Security (DTLS) handshakes.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.