Process-teardown hang via nested deferred-unlock race
Published Sep 17, 2026 · Updated Sep 17, 2026
A locking race in Linux kernel BPF allows local users to hang process teardown through nested deferred memory-map unlocks. stack_map_get_build_id_offset() and bpf_find_vma() check the shared per-CPU mmap_unlock_work slot without reserving it, allowing nested calls to acquire two read locks but schedule only one unlock. Exploitation requires reaching the affected BPF paths and the nesting window; the leaked mmap_lock blocks exit_mmap(), with no disclosed data access or code execution.
Summary
What happened
A locking race in Linux kernel BPF allows local users to hang process teardown through nested deferred memory-map unlocks. stack_map_get_build_id_offset() and bpf_find_vma() check the shared per-CPU mmap_unlock_work slot without reserving it, allowing nested calls to acquire two read locks but schedule only one unlock. Exploitation requires reaching the affected BPF paths and the nesting window; the leaked mmap_lock blocks exit_mmap(), with no disclosed data access or code execution.
The record
- CVE
- CVE-2026-90247
- Published
- Sep 17, 2026
- Updated
- Sep 17, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 17, 2026CVE publishedPublication date reported by the CVE source.
- Sep 17, 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=4.19.92 <4.20
- Affected versionversion=5.4.7 <5.5
- Affected versionversion=5.5
- Affected versionversion=a7f4da875c16f3b8bef0d9ec67528111045bfcd8
- Affected versionversion=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <051f2da26ce377f683b938a3382e0f16d02f3139
- Affected versionversion=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <a052ad5edccf5319f50ed955de4368f8318a9f20
- Affected versionversion=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <fa9dcacdcdf487f0ffef64bf67622f1caed509f1
- Affected versionversion=f1838da73cccb238b8be4ef464fce0168dc7ba84
What conditions does exploitation require?
What is affected?
Published CVSS scores
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
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