cvedb.io
CVE-2026-33278
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2026-05-20T10:16:26.530 · Last modified 2026-06-30T03:18:39.590

Summary

NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or p

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.