CVE-2025-11411

Name	CVE-2025-11411
Description	NLnet Labs Unbound up to and including version 1.24.2 is vulnerable to possible domain hijack attacks. Promiscuous NS RRSets that complement positive DNS replies in the authority section can be used to trick resolvers to update their delegation information for the zone. Usually these RRSets are used to update the resolver's knowledge of the zone's name servers. A malicious actor can exploit the possible poisonous effect by injecting NS RRSets (and possibly their respective address records) in a reply. This could be done for example by trying to spoof a packet or fragmentation attacks. Unbound would then proceed to update the NS RRSet data it already has since the new data has enough trust for it, i.e., in-zone data for the delegation point. Unbound 1.24.1 includes a fix that scrubs unsolicited NS RRSets (and their respective address records) from replies mitigating the possible poison effect. Unbound 1.24.2 includes an additional fix that scrubs unsolicited NS RRSets (and their respective address records) from YXDOMAIN and non-referral nodata replies, further mitigating the possible poison effect.
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)
References	DLA-4365-1, DLA-4365-2, DSA-6071-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
unbound (PTS)	bullseye	1.13.1-1+deb11u2	vulnerable
	bullseye (security)	1.13.1-1+deb11u7	fixed
	bookworm, bookworm (security)	1.17.1-2+deb12u3	vulnerable
	trixie	1.22.0-2	vulnerable
	trixie (security)	1.22.0-2+deb13u1	fixed
	forky, sid	1.24.2-1	fixed

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

Package	Type	Release	Fixed Version	Origin
unbound	source	bullseye	1.13.1-1+deb11u7	DLA-4365-2
unbound	source	trixie	1.22.0-2+deb13u1	DSA-6071-1
unbound	source	(unstable)	1.24.2-1

Notes

[bookworm] - unbound <no-dsa> (Minor issue; will be fixed via point release for more exposure before release)
https://www.nlnetlabs.nl/downloads/unbound/CVE-2025-11411.txt
Fixed by: https://github.com/NLnetLabs/unbound/commit/a33f0638e1dacf2633cf2292078a674576bca852 (release-1.24.1)
The original fix for CVE-2025-11411 was incomplete and required a followup
(cf. https://bugs.debian.org/1121446) to include YXDOMAIN and non-referral
nodata answers in the mitigation as well:
Followup: https://github.com/NLnetLabs/unbound/commit/f6269baa605d31859f28770e01a24e3677e5f82c (release-1.24.2)