Improper input validation in Linux kernel - CVE-2026-72111

Vulnerability details

The vulnerability allows a local user to bypass BPF memory safety checks.

The vulnerability exists due to improper register state handling in check_mem_access() in the BPF verifier when processing a context load of an LSM hook return value. A local user can load a hook return value into a register with stale bounds to bypass BPF memory safety checks.

The issue arises from a verifier/runtime mismatch because the verifier may treat the register as having a narrower range than the actual runtime value.

Affected software

How to mitigate CVE-2026-72111

External References

• https://git.kernel.org/stable/c/0993dc5fc619c0b25ab1310cb11d65e78351c0fe
• https://git.kernel.org/stable/c/5a55f9aecc08990940e70f0c7048a80850c5a16a
• https://git.kernel.org/stable/c/5e0b273e0a62cc04ec338c7b502797c66c2ed42a
• https://git.kernel.org/stable/c/bde92f65042ec14389782dd223f706bf6b59ce5d

Related Security Bulletins

• Improper input validation in Linux kernel bpf
• Debian update for linux