CVE-2026-123603

Name	CVE-2026-123603
Description	hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients.
Source	CVE (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 Package	Release	Version	Status
rust-hickory-proto (PTS)	trixie	0.24.4-2	vulnerable
	forky, sid	0.26.3-1	fixed
rust-hickory-recursor (PTS)	trixie	0.24.1-1	vulnerable
	forky, sid	0.25.2-6	vulnerable
rust-hickory-resolver (PTS)	trixie	0.24.4-1	vulnerable
	forky, sid	0.26.3-1	fixed
rust-hickory-server (PTS)	trixie	0.24.4-2	vulnerable
	forky, sid	0.26.3-1	fixed

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

Package	Type	Release	Fixed Version
rust-hickory-proto	source	(unstable)	0.26.3-1
rust-hickory-recursor	source	(unstable)	(unfixed)
rust-hickory-resolver	source	(unstable)	0.26.3-1
rust-hickory-server	source	(unstable)	0.26.3-1

https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g