Local privilege escalation via unlocked hwtstamp callbacks
Published Oct 1, 2025 · Updated Aug 5, 2026
Race condition in Linux kernel 6.15 through 6.16.7 allows local users to escalate privileges through hardware-timestamp ioctls. The lower hardware-timestamp get and set paths invoke device callbacks without the required per-device operations lock, permitting races with queue reconfiguration that cause use-after-free and out-of-bounds access. Reachability requires a stacked network device over an operations-locked NIC; successful races can expose or overwrite kernel memory or crash the host.
Summary
What happened
Race condition in Linux kernel 6.15 through 6.16.7 allows local users to escalate privileges through hardware-timestamp ioctls. The lower hardware-timestamp get and set paths invoke device callbacks without the required per-device operations lock, permitting races with queue reconfiguration that cause use-after-free and out-of-bounds access. Reachability requires a stacked network device over an operations-locked NIC; successful races can expose or overwrite kernel memory or crash the host.
The record
- CVE
- CVE-2025-39908
- Published
- Oct 1, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 1, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record 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=6.15
- Affected versionversion=ffb7ed19ac0a9fa9ea79af1d7b42c03a10da98a5 <2d92fa0cdc02291de57f72170e8b60cef0cf5372
- Affected versionversion=ffb7ed19ac0a9fa9ea79af1d7b42c03a10da98a5 <686cab5a18e443e1d5f2abb17bed45837836425f
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
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Technologies
Your stack
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Your stack
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