CVE-2026-43333: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 5.15.37, before 5.15.203 (fixed in 5.15.203); from 5.16.11, before 6.1.168 (fixed in 6.1.168); from 6.2, before 6.6.134 (fixed in 6.6.134); from 6.7, before 6.12.81 (fixed in 6.12.81); from 6.13, before 6.18.22 (fixed in 6.18.22); from 6.19, before 6.19.12 (fixed in 6.19.12); …

Published 2026-05-08. Last modified 2026-06-17.