CVE-2026-53218

Name	CVE-2026-53218
Description	In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_exthdr: fix register tracking for F_PRESENT flag nft_exthdr_init() passes user-controlled priv->len to nft_parse_register_store(), which marks that many bytes in the register bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT is set, the eval paths write only 1 byte (nft_reg_store8) or 4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4, registers beyond the first are never written, retaining uninitialized stack data from nft_regs. Bail out if userspace requests too much data when F_PRESENT is set.
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-4664-1, DLA-4665-1, DLA-4671-1

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)	5.10.259-1	fixed
	bookworm, bookworm (security)	6.1.176-1	fixed
	trixie	6.12.94-1	fixed
	trixie (security)	6.12.95-1	fixed
	forky, sid	7.1.3-1	fixed
linux-6.1 (PTS)	bullseye (security)	6.1.176-1~deb11u1	fixed

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

Package	Type	Release	Fixed Version	Origin
linux	source	bullseye	5.10.259-1	DLA-4664-1
linux	source	bookworm	6.1.176-1	DLA-4665-1
linux	source	trixie	6.12.94-1
linux	source	(unstable)	7.0.13-1
linux-6.1	source	bullseye	6.1.176-1~deb11u1	DLA-4671-1

https://git.kernel.org/linus/772cecf198da732faebb5dcfc46d66a505be8495 (7.1)