CVE-2025-21759

Name	CVE-2025-21759
Description	In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.
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
linux (PTS)	bullseye	5.10.223-1	vulnerable
	bullseye (security)	5.10.244-1	vulnerable
	bookworm	6.1.148-1	vulnerable
	bookworm (security)	6.1.153-1	vulnerable
	trixie	6.12.43-1	fixed
	trixie (security)	6.12.48-1	fixed
	forky	6.16.12-2	fixed
	sid	6.17.7-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	(unstable)	6.12.16-1

https://git.kernel.org/linus/087c1faa594fa07a66933d750c0b2610aa1a2946 (6.14-rc3)