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Findings

CVE-2026-42009

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

Published May 18, 2026 · updated Oct 14, 2026

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.

Timeline

Detection, updates, and resolution for this record.

  1. May 18, 2026 · Catalog

    Detected

    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.

  2. Oct 14, 2026 · Catalog

    Updated

    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.

Affected

  • vendor Red Hat Red Hat Enterprise Linux 10version unspecified
  • vendor Red Hat Red Hat Enterprise Linux 10.0 Extended Update Supportversion unspecified
  • vendor Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Supportversion unspecified
  • vendor Red Hat Red Hat Enterprise Linux 8version unspecified
  • vendor Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportversion unspecified

Sources

  • CIRCL Vulnerability LookupCVE-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 sequen

    vulnerability.circl.lu

References