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Vulnerability record · CVE-2026-42009 · published 18 May 2026

CVE-2026-42009: Gnutls vulnerability

Gnu · Gnutls

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.

7.5 CVSS 3.1 High EPSS 1.1% · top 35.0% CWE-475 · CWE-475
7.5CVSS 3.1 base score
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
14Affected product versions listed by NVD
64References
18 Sep 2026Last modified by NVD

Description

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.

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

Affected products

14 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2026:13274 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20611 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20612 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20613 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:26319
https://access.redhat.com/errata/RHSA-2026:26409
https://access.redhat.com/errata/RHSA-2026:29197
https://access.redhat.com/errata/RHSA-2026:29794
https://access.redhat.com/errata/RHSA-2026:30004
https://access.redhat.com/errata/RHSA-2026:30849
https://access.redhat.com/errata/RHSA-2026:30850
https://access.redhat.com/errata/RHSA-2026:32962
https://access.redhat.com/errata/RHSA-2026:33125
https://access.redhat.com/errata/RHSA-2026:34372
https://access.redhat.com/errata/RHSA-2026:34764
https://access.redhat.com/errata/RHSA-2026:34788
https://access.redhat.com/errata/RHSA-2026:36004
https://access.redhat.com/errata/RHSA-2026:36005
https://access.redhat.com/errata/RHSA-2026:36006
https://access.redhat.com/errata/RHSA-2026:40762
https://access.redhat.com/errata/RHSA-2026:41921
https://access.redhat.com/errata/RHSA-2026:56786
https://access.redhat.com/errata/RHSA-2026:56853
https://access.redhat.com/errata/RHSA-2026:56911
https://access.redhat.com/errata/RHSA-2026:57483
https://access.redhat.com/errata/RHSA-2026:58981
https://access.redhat.com/errata/RHSA-2026:59831
https://access.redhat.com/errata/RHSA-2026:60019
https://access.redhat.com/errata/RHSA-2026:65839
https://access.redhat.com/security/cve/CVE-2026-42009 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2467279 Issue TrackingThird Party Advisory
https://www.gnutls.org/security-new.html#GNUTLS-SA-2026-04-29-2
https://access.redhat.com/errata/RHSA-2026:13274 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20611 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20612 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:20613 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:26319
https://access.redhat.com/errata/RHSA-2026:26409
https://access.redhat.com/errata/RHSA-2026:29197
https://access.redhat.com/errata/RHSA-2026:29794

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Source: NIST National Vulnerability Database (record CVE-2026-42009), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.