CVE-2026-33278 - Possible arbitrary code execution during DNSSEC validation

CVE-2026-33278 - Possible arbitrary code execution during DNSSEC validation

https://cvefeed.io/rssfeed/latest.atom / Wed, 05/20/2026 - 14:24
CVE ID :CVE-2026-33278
Published : May 20, 2026, 10:16 a.m. | 42 minutes ago
Description :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 potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.
Severity: 9.1 | CRITICAL
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