Kernel memory corruption via stale BFQ cgroup state
Published Feb 26, 2025 · Updated Aug 5, 2026
Use-after-free in BFQ in affected Linux kernel versions allows local users to corrupt kernel memory through block I/O after a cgroup change. The bfq_merge_bio() path uses stale cgroup information in bfq_io_cq, allowing bios to merge with BFQ queues from another or already-dead cgroup. Local low-privileged access, BFQ I/O scheduling, and a process migration or writeback bio for a different cgroup are required; the fault can crash the host or corrupt kernel memory.
Summary
What happened
Use-after-free in BFQ in affected Linux kernel versions allows local users to corrupt kernel memory through block I/O after a cgroup change. The bfq_merge_bio() path uses stale cgroup information in bfq_io_cq, allowing bios to merge with BFQ queues from another or already-dead cgroup. Local low-privileged access, BFQ I/O scheduling, and a process migration or writeback bio for a different cgroup are required; the fault can crash the host or corrupt kernel memory.
The record
- CVE
- CVE-2022-49413
- Published
- Feb 26, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 26, 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=4.12
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <2a1077f17169a6059992a0bbdb330e0abad1e6d9
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <b06691af08b41dfd81052a3362514d9827b44bb1
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <d9165200c5627a2cf4408eefabdf0058bdf95e1a
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <da9f3025d595956410ceaab2bea01980d7775948
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <e8821f45612f2e6d9adb9c6ba0fb4184f57692aa
- Affected versionversion=e21b7a0b988772e82e7147e1c659a5afe2ae003c <ea591cd4eb270393810e7be01feb8fde6a34fbbe
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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Public exploit references
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Technologies
Your stack
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Your stack
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