---
id: CVE-2026-90317
title: |-
  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
summary: |-
  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(…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 <
    7ae71629357d0a6d0bdadb929c7b296d5b7e61c2
  - >-
    Linux >= 5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 <
    180c7000712db77063b3a26f4c97e7dd9038f449
  - Linux 6.6
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:53.437'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90317'
references:
  - url: 'https://git.kernel.org/stable/c/180c7000712db77063b3a26f4c97e7dd9038f449'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7ae71629357d0a6d0bdadb929c7b296d5b7e61c2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00165
epssPercentile: 0.05074
ingestedAt: '2026-09-17T16:21:47.824Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.