Unbound 1.19.2 released

Published: Thu 07 March 2024
Last updated: Fri 19 April 2024

We are pleased to announce the release of version 1.19.2 of the Unbound recursive DNS resolver.

This security release fixes CVE-2024-1931.

NLnet Labs Unbound version 1.18.0 up to and including version 1.19.1 contain a vulnerability that can cause denial of service by a certain code path that can lead to an infinite loop.

Unbound 1.18.0 introduced a feature that removes EDE records from responses with size higher than the client's advertised buffer size. Before removing all the EDE records however, it would try to see if trimming the extra text fields on those records would result in an acceptable size while still retaining the EDE codes. Due to an unchecked condition, the code that trims the text of the EDE records could loop indefinitely. This happens when Unbound would reply with attached EDE information on a positive reply and the client's buffer size is smaller than the needed space to include EDE records.

The vulnerability can only be triggered when the 'ede: yes' option is used; non default configuration.

From version 1.19.2 on, the code is fixed to avoid looping indefinitely.

We would like to thank Fredrik Pettai and Patrik Lundin from SUNET for notifying us about the issue and working with us to identify the vulnerability.

For a full list of changes, binary and source packages, see the download page.

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