Fiche vulnérabilité
CVE-2026-42944 : faille élevée nlnetlabs unbound (CVSS 7.5)
Description
NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.
En bref
- Sévérité
- Élevée (CVSS 7.5)
- Vecteur CVSS
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Exploitation active
- Non signalée par la CISA
- Publication
- 20 mai 2026
- Dernière mise à jour
- 26 août 2026
Produits concernés
- nlnetlabs unbound
Références
- Fiche CVE-2026-42944 sur le NVD (NIST)
- nlnetlabs.nl/downloads/unbound/CVE-2026-42944.txt
- access.redhat.com/errata/RHSA-2026:19752
- access.redhat.com/errata/RHSA-2026:23231
- access.redhat.com/errata/RHSA-2026:24365
- access.redhat.com/errata/RHSA-2026:24369
- access.redhat.com/security/cve/CVE-2026-42944
- bugzilla.redhat.com/show_bug.cgi
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42944.json