CVE-2026-42009 HIGH

CVE-2026-42009: Gnutls: gnutls: denial of service via dtls packet reordering vulnerability

Vendor Red Hat
Product Red Hat Enterprise Linux 6
Weakness CWE-475
Published May 18, 2026
Last update July 1, 2026

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 18, 2026 CVE published
July 1, 2026 Record updated