Kernel crash via btrfs unmount race
Published Jan 15, 2025 · Updated Aug 5, 2026
Use-after-free in Linux kernel btrfs before fixed stable releases allows local users to crash the kernel during filesystem unmount. close_ctree() stops and frees the cleaner thread before draining delalloc_workers, allowing submit_compressed_extents() to call btrfs_add_delayed_iput() and wake the freed task. Reaching the race requires local privileges sufficient to unmount an active btrfs filesystem, and the demonstrated consequence is kernel memory corruption and a host crash.
Summary
What happened
Use-after-free in Linux kernel btrfs before fixed stable releases allows local users to crash the kernel during filesystem unmount. close_ctree() stops and frees the cleaner thread before draining delalloc_workers, allowing submit_compressed_extents() to call btrfs_add_delayed_iput() and wake the freed task. Reaching the race requires local privileges sufficient to unmount an active btrfs filesystem, and the demonstrated consequence is kernel memory corruption and a host crash.
The record
- CVE
- CVE-2024-57896
- Published
- Jan 15, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 15, 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?
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- Affected versionversion=5.0
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <1ea629e7bb2fb40555e5e01a1b5095df31287017
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <35916b2f96505a18dc7242a115611b718d9de725
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <63f4b594a688bf922e8691f0784679aa7af7988c
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <a2718ed1eb8c3611b63f8933c7e68c8821fe2808
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <d77a3a99b53d12c061c007cdc96df38825dee476
- Affected versionversion=fd340d0f68cc87badfc9efcb226f23a5428826a0 <f10bef73fb355e3fc85e63a50386798be68ff486
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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