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ALPINE-CVE-2026-42944

ALPINE-CVE-2026-42944

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 7.5 · High · Fix available

Published
Updated

Stack: system

Affected products and versions

  • unbound Alpine:v3.22

    Affected ranges
    • ECOSYSTEM: ≥ 1.14.0, < 1.25.2-r0

    Update to 1.25.2-r0

  • unbound Alpine:v3.23

    Affected ranges
    • ECOSYSTEM: ≥ 1.14.0, < 1.25.2-r0

    Update to 1.25.2-r0

  • unbound Alpine:v3.24

    Affected ranges
    • ECOSYSTEM: ≥ 1.14.0, < 1.25.1-r0

    Update to 1.25.1-r0

Original sources

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