CVE-2025-40173

Name	CVE-2025-40173
Description	In the Linux kernel, the following vulnerability has been resolved: net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer.
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)	6.1.158-1	fixed
	trixie	6.12.43-1	vulnerable
	trixie (security)	6.12.48-1	vulnerable
	forky	6.16.12-2	vulnerable
	sid	6.17.7-2	fixed

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

Package	Type	Release	Fixed Version
linux	source	bookworm	6.1.158-1
linux	source	trixie	6.12.57-1
linux	source	(unstable)	6.17.6-1

https://git.kernel.org/linus/21f4d45eba0b2dcae5dbc9e5e0ad08735c993f16 (6.18-rc2)