Always-Incorrect Control Flow Implementation in GnuTLS - CVE-2026-42009
Published: April 30, 2026
Vulnerability identifier: #VU128569
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42009
CWE-ID: CWE-670
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: GnuTLS
Affected software:
GnuTLS
GnuTLS
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper implementation of a qsort comparator contract in the DTLS packet sequence number comparator when ordering DTLS packets by sequence numbers. A remote attacker can send DTLS packets with duplicate sequence numbers to cause a denial of service.
How to mitigate CVE-2026-42009
Install security update from vendor's website.