CVE-2026-90250

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux0c991ebc8c69d29b7fc44db17075c5aa5253e2ab < a033c950f6731be88a7da98604ed78f302f15b80affected
LinuxLinux0c991ebc8c69d29b7fc44db17075c5aa5253e2ab < 1ab3da12061d7ccb099f7e925fa2d865967a316aaffected
LinuxLinux0c991ebc8c69d29b7fc44db17075c5aa5253e2ab < 12feca126831556dc7fabe5a3ba28fbd328768b6affected
LinuxLinux0c991ebc8c69d29b7fc44db17075c5aa5253e2ab < 3f562c537e9ecf4bc5e206cfffc2cc047f1b7e94affected
LinuxLinux5.7affected
LinuxLinux0 < 5.7unaffected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.52 <= 6.18.*unaffected
LinuxLinux7.2.6 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References