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.
Advisories

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Fixes

Solution

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Workaround

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History

Thu, 17 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
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.
Title bpf, cgroup: Fix storage null-ptr-deref after replacing prog
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-17T16:07:51.403Z

Reserved: 2026-09-11T19:38:34.795Z

Link: CVE-2026-90250

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-17T17:17:21.237

Modified: 2026-09-17T17:17:21.237

Link: CVE-2026-90250

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.