Description
In the Linux kernel, the following vulnerability has been resolved:

bpf: Invalidate RCU pointers after final spin unlock

In a sleepable BPF program, a spin lock can provide the only RCU protection
for a kptr. The final bpf_spin_unlock() ends that protection, but the
verifier leaves the pointer valid. Another CPU can then free the object
before the pointer is used. A capability-limited runtime PoC triggered a
task_struct use-after-free in __bpf_get_task_stack().

Record whether the program is in an RCU-protected context before releasing
the lock. Invalidate RCU-protected pointers only when the unlock leaves the
final such context. This preserves valid pointers in non-sleepable programs
and inside an explicit RCU read-side section.
Published: 2026-09-17
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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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: Invalidate RCU pointers after final spin unlock In a sleepable BPF program, a spin lock can provide the only RCU protection for a kptr. The final bpf_spin_unlock() ends that protection, but the verifier leaves the pointer valid. Another CPU can then free the object before the pointer is used. A capability-limited runtime PoC triggered a task_struct use-after-free in __bpf_get_task_stack(). Record whether the program is in an RCU-protected context before releasing the lock. Invalidate RCU-protected pointers only when the unlock leaves the final such context. This preserves valid pointers in non-sleepable programs and inside an explicit RCU read-side section.
Title bpf: Invalidate RCU pointers after final spin unlock
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-17T16:08:35.537Z

Reserved: 2026-09-11T19:38:34.801Z

Link: CVE-2026-90317

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-17T17:17:29.580

Modified: 2026-09-17T17:17:29.580

Link: CVE-2026-90317

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

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