Description
In the Linux kernel, the following vulnerability has been resolved:
bpf, cgroup: Fix storage null-ptr-deref after replacing prog
Syzkaller reported a storage null-ptr-deref issue after replacing prog. This occurs in the following scenario: 1. prog A, an empty prog, is attached to a cgrp. 2. prog B uses BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE and calls the bpf_get_local_storage helper. 3. link_update is called to replace prog A with prog B.
The reason is that __cgroup_bpf_replace fails to alloc and assign the required cgrp storage for the incoming replacement prog. Consequently, the new prog inherits an uninit storage, leading to null-ptr-deref panic when kick the new prog.
Fix this by rejecting a link update if new_prog's cgroup storage is incompatible with link->prog.
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
No affected versions have been published.
Timeline
- Published
- Sep 17, 2026
- Last modified
- Oct 21, 2026
- NVD status
- Received