CVE-2026-50106

NameCVE-2026-50106
DescriptionWhen NLnet Labs Unbound up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for an island-of-security zone whose parent is provably insecure under the root chain, a malicious actor who can deliver one forged NXDOMAIN response for a name inside the island, with the NSEC/SOA RRSIG 'SignerName' set to the insecure parent, tricks Unbound's validator to use the root trust anchor instead, and consecutively the insecure parent, thus causing that record to be treated as insecure and denying existence for records in the trust island.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6581-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
unbound (PTS)bookworm1.17.1-2+deb12u4vulnerable
bookworm (security)1.17.1-2+deb12u3vulnerable
trixie1.22.0-2+deb13u3vulnerable
trixie (security)1.26.2-0+deb13u1fixed
forky, sid1.26.2-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
unboundsourcetrixie1.26.2-0+deb13u1DSA-6581-1
unboundsource(unstable)1.26.2-1

Notes

https://community.nlnetlabs.nl/t/unbound-1-26-2-released/3495

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