Kernel panic via blk-mq elevator-switch race
Published Oct 7, 2025 · Updated Oct 7, 2025
Use-after-free in the Linux kernel blk-mq subsystem allows local users with CAP_SYS_ADMIN to trigger a kernel panic during queue reinitialization. blk_mq_realloc_hw_ctxs freezes the queue without quiescing hctx run_work, so worker code can dereference an elevator pointer while the elevator is being torn down. Reaching the race requires CAP_SYS_ADMIN in the initial user namespace or equivalent root-only sysfs access, and the bounded consequence is a host crash.
Summary
What happened
Use-after-free in the Linux kernel blk-mq subsystem allows local users with CAP_SYS_ADMIN to trigger a kernel panic during queue reinitialization. blk_mq_realloc_hw_ctxs freezes the queue without quiescing hctx run_work, so worker code can dereference an elevator pointer while the elevator is being torn down. Reaching the race requires CAP_SYS_ADMIN in the initial user namespace or equivalent root-only sysfs access, and the bounded consequence is a host crash.
The record
- CVE
- CVE-2022-50552
- Published
- Oct 7, 2025
- Updated
- Oct 7, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Oct 7, 2025CVE publishedPublication date reported by the CVE source.
- Oct 7, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <63a681bcc32a43528ce0f690569f7f48e59c3963
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8237c01f1696bc53c470493bf1fe092a107648a6
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c478b3b2900f1834cf9eda5bfef0d5696099505d
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Published CVSS scores
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Attacks
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Technologies
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