CVE-2026-43333

Name	CVE-2026-43333
Description	In the Linux kernel, the following vulnerability has been resolved: bpf: reject direct access to nullable PTR_TO_BUF pointers check_mem_access() matches PTR_TO_BUF via base_type() which strips PTR_MAYBE_NULL, allowing direct dereference without a null check. Map iterator ctx->key and ctx->value are PTR_TO_BUF \| PTR_MAYBE_NULL. On stop callbacks these are NULL, causing a kernel NULL dereference. Add a type_may_be_null() guard to the PTR_TO_BUF branch, matching the existing PTR_TO_BTF_ID pattern.
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	fixed
	bullseye (security)	5.10.251-4	fixed
	bookworm	6.1.159-1	vulnerable
	bookworm (security)	6.1.170-1	fixed
	trixie	6.12.73-1	vulnerable
	trixie (security)	6.12.86-1	fixed
	forky	6.19.14-1	fixed
	sid	7.0.4-1	fixed

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

Package	Type	Release	Fixed Version
linux	source	bullseye	(not affected)
linux	source	bookworm	6.1.170-1
linux	source	trixie	6.12.85-1
linux	source	(unstable)	6.19.12-1

[bullseye] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/b0db1accbc7395657c2b79db59fa9fae0d6656f3 (7.0-rc7)