MNBSD-2026-51: jostle logic bypass degrades resolution performance

Description

A bypass of the jostle-over-limit logic degrades resolution performance, enabling a Denial of Service. Reported by Qifan Zhang, Palo Alto Networks.

Affected Versions

unbound

Recommendations

No specific recommendations provided.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-42534
• https://nlnetlabs.nl/projects/unbound/security-advisories/

Additional Information

Aliases: CVE-2026-42534

Published: June 11, 2026
Last Modified: June 11, 2026