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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No vendor fix or workaround currently provided.
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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 |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:07:51.403Z
Reserved: 2026-09-11T19:38:34.795Z
Link: CVE-2026-90250
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:21.237
Modified: 2026-09-17T17:17:21.237
Link: CVE-2026-90250
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.