cvedb.io
CVE-2026-42534
MEDIUM · CVSS 5.3
EPSS exploitation probability: 0%
Published 2026-05-20T10:16:27.477 · Last modified 2026-06-30T03:19:38.620

Summary

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then h

Affected products

nlnetlabs — unbound

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.