Kernel use-after-free via stale RCU-protected BPF pointer
Published Sep 17, 2026 · Updated Sep 18, 2026
Use-after-free in the Linux kernel BPF verifier from 6.6 allows local users to access freed task_struct memory through a sleepable BPF program. After the final bpf_spin_unlock() ends the only RCU-protected context, process_spin_lock() leaves a kptr valid instead of invalidating its RCU-protected reference. Triggering the flaw requires permission to load a crafted sleepable BPF program and a race in which another CPU frees the referenced task before __bpf_get_task_stack() uses it.
Summary
What happened
Use-after-free in the Linux kernel BPF verifier from 6.6 allows local users to access freed task_struct memory through a sleepable BPF program. After the final bpf_spin_unlock() ends the only RCU-protected context, process_spin_lock() leaves a kptr valid instead of invalidating its RCU-protected reference. Triggering the flaw requires permission to load a crafted sleepable BPF program and a race in which another CPU frees the referenced task before __bpf_get_task_stack() uses it.
The record
- CVE
- CVE-2026-90317
- Published
- Sep 17, 2026
- Updated
- Sep 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 17, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 <180c7000712db77063b3a26f4c97e7dd9038f449
- Affected versionversion=5861d1e8dbc4e1a03ebffb96ac041026cdd34c07 <7ae71629357d0a6d0bdadb929c7b296d5b7e61c2
- Affected versionversion=6.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started