System hang via interrupt-context lock deadlock
Published Mar 12, 2025 · Updated May 11, 2026
Improper locking in Linux kernel 6.9 through 6.12.16 and 6.13 through 6.13.4 allows local users to hang systems through an i915 race. The guc_lrc_desc_unpin() and signal_irq_work() paths acquire spinlocks without saving and disabling interrupt state, so an interrupt can reacquire a held lock and deadlock the kernel. Exploitation requires local low-privileged access and execution of the affected Intel i915 GuC path; the documented consequence is service interruption, not data access or modification.
Summary
What happened
Improper locking in Linux kernel 6.9 through 6.12.16 and 6.13 through 6.13.4 allows local users to hang systems through an i915 race. The guc_lrc_desc_unpin() and signal_irq_work() paths acquire spinlocks without saving and disabling interrupt state, so an interrupt can reacquire a held lock and deadlock the kernel. Exploitation requires local low-privileged access and execution of the affected Intel i915 GuC path; the documented consequence is service interruption, not data access or modification.
The record
- CVE
- CVE-2025-21849
- Published
- Mar 12, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-667, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 12, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 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=2f2cc53b5fe7022f3ae602eb24573d52f8740959 <2bf1f4c129db7a10920655b000f0292f1ee509c2
- Affected versionversion=2f2cc53b5fe7022f3ae602eb24573d52f8740959 <47ae46ac5407646420e06b78e0dad331e56a4bb4
- Affected versionversion=2f2cc53b5fe7022f3ae602eb24573d52f8740959 <e49477f7f78598295551d486ecc7f020d796432e
- Affected versionversion=6.9
What conditions does exploitation require?
What is affected?
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.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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