CVE-2026-56416 Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name

In NLnet Labs Unbound up to and including version 1.25.1, when the validator builds the canonical RDATA form for an RRSIG-covered PX/RP/MINFO/SOA RRset, it computes the address of the second embedded domain name as 'datstart + dnamevaliddatstart, ...' and passes it straight to 'querydnametolower'...

CVE-2026-56416

Technical details required to assess impact are not publicly available in the provided documents. No additional specifics (versions beyond 1.25.1, exploitation paths, or fixes) are included. Monitor for updates.