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.

References

• https://git.kernel.org/stable/c/10bc4a4dcded509c5d5c67d497900c3922c604cd
• https://git.kernel.org/stable/c/21a10c06ffae24cb01fd174a7ab7736001d2ea56
• https://git.kernel.org/stable/c/4f6c99dc0420f1a3d671c1b8ab8a7ac84d9cba09
• https://git.kernel.org/stable/c/63276547debc4d8a73eefb2c5273b2a905c961b0
• https://git.kernel.org/stable/c/70abd9d118da2f56beb4ec22e3a29becae373535
• https://git.kernel.org/stable/c/8755066f7bd0f4ac46a29d1708c7b20894539252
• https://git.kernel.org/stable/c/b0db1accbc7395657c2b79db59fa9fae0d6656f3