Filesystem corruption via duplicate block freeing
Published Feb 24, 2024 · Updated Aug 5, 2026
Filesystem metadata corruption in Linux allows local users to corrupt ext4 allocation state by mounting a crafted fast-commit image. During replay in fs/ext4/mballoc.c, mb_free_blocks() can mark already-free blocks free again without regenerating the allocator's buddy bitmap, leaving its free-space views inconsistent. Reachability requires a locally supplied block device or mountable image with fast-commit records; subsequent allocation can expose or overwrite file data or panic the host.
Summary
What happened
Filesystem metadata corruption in Linux allows local users to corrupt ext4 allocation state by mounting a crafted fast-commit image. During replay in fs/ext4/mballoc.c, mb_free_blocks() can mark already-free blocks free again without regenerating the allocator's buddy bitmap, leaving its free-space views inconsistent. Reachability requires a locally supplied block device or mountable image with fast-commit records; subsequent allocation can expose or overwrite file data or panic the host.
The record
- CVE
- CVE-2024-26601
- Published
- Feb 24, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 24, 2024CVE 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=0983142c5f17a62055ec851372273c3bc77e4788 <94ebf71bddbcd4ab1ce43ae32c6cb66396d2d51a
- Affected versionversion=5.10.181 <5.10.211
- Affected versionversion=5.11
- Affected versionversion=6bd97bf273bdb4944904e57480f6545bca48ad77 <6b0d48647935e4b8c7b75d1eccb9043fcd4ee581
- Affected versionversion=6bd97bf273bdb4944904e57480f6545bca48ad77 <78327acd4cdc4a1601af718b781eece577b6b7d4
- Affected versionversion=6bd97bf273bdb4944904e57480f6545bca48ad77 <c1317822e2de80e78f137d3a2d99febab1b80326
- Affected versionversion=6bd97bf273bdb4944904e57480f6545bca48ad77 <c9b528c35795b711331ed36dc3dbee90d5812d4e
- Affected versionversion=6bd97bf273bdb4944904e57480f6545bca48ad77 <ea42d6cffb0dd27a417f410b9d0011e9859328cb
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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