CVE-2026-54478

NameCVE-2026-54478
DescriptionIn NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
unbound (PTS)bullseye1.13.1-1+deb11u2vulnerable
bullseye (security)1.13.1-1+deb11u7vulnerable
bookworm1.17.1-2+deb12u4vulnerable
bookworm (security)1.17.1-2+deb12u3vulnerable
trixie (security), trixie1.22.0-2+deb13u3vulnerable
forky, sid1.26.0-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
unboundsource(unstable)1.25.2-1

Notes

https://community.nlnetlabs.nl/t/unbound-1-25-2-released/3430

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