Kernel lock corruption via wrong fork failure exit
Published Oct 15, 2025 · Updated Oct 15, 2025
Improper lock handling in Linux 6.16 through 6.16.9 allows local users to corrupt kernel lock state during failed process creation. copy_process sends a futex_hash_allocate_default failure to bad_fork_core_free, which unlocks tasklist_lock and siglock even though neither lock was acquired. Low-privileged local access is required; upstream reports the unsafe lock release but no concrete exploit sequence or final failure mode.
Summary
What happened
Improper lock handling in Linux 6.16 through 6.16.9 allows local users to corrupt kernel lock state during failed process creation. copy_process sends a futex_hash_allocate_default failure to bad_fork_core_free, which unlocks tasklist_lock and siglock even though neither lock was acquired. Low-privileged local access is required; upstream reports the unsafe lock release but no concrete exploit sequence or final failure mode.
The record
- CVE
- CVE-2025-39976
- Published
- Oct 15, 2025
- Updated
- Oct 15, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 15, 2025CVE publishedPublication date reported by the CVE source.
- Oct 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.16
- Affected versionversion=7c4f75a21f636486d2969d9b6680403ea8483539 <4ec3c15462b9f44562f45723a92e2807746ba7d1
- Affected versionversion=7c4f75a21f636486d2969d9b6680403ea8483539 <f1635765cd0fdbf27b04d9a50be91a01b5adda13
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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