Filesystem corruption via unlocked block-bitmap check
Published Apr 3, 2024 · Updated Aug 5, 2026
Race condition in the Linux kernel's ext4 allocator allows local users to disclose or corrupt filesystem data and crash the kernel. ext4_mb_find_by_goal() checks EXT4_GROUP_INFO_BBITMAP_CORRUPT before taking the group lock, allowing a concurrent corruption update to be missed and blocks from a known-corrupt group to be allocated. An unprivileged account with a writable directory on a mounted ext4 filesystem can race its own file operations, causing cross-file data exposure or modification, read-only remounts, ENOSPC, or a kernel panic.
Summary
What happened
Race condition in the Linux kernel's ext4 allocator allows local users to disclose or corrupt filesystem data and crash the kernel. ext4_mb_find_by_goal() checks EXT4_GROUP_INFO_BBITMAP_CORRUPT before taking the group lock, allowing a concurrent corruption update to be missed and blocks from a known-corrupt group to be allocated. An unprivileged account with a writable directory on a mounted ext4 filesystem can race its own file operations, causing cross-file data exposure or modification, read-only remounts, ENOSPC, or a kernel panic.
The record
- CVE
- CVE-2024-26772
- Published
- Apr 3, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 3, 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?
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- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <21dbe20589c7f48e9c5d336ce6402bcebfa6d76a
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <5a6dcc4ad0f7f7fa8e8d127b5526e7c5f2d38a43
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <6b92b1bc16d691c95b152c6dbf027ad64315668d
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <832698373a25950942c04a512daa652c18a9b513
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <8de8305a25bfda607fc13475ebe84b978c96d7ff
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <d3bbe77a76bc52e9d4d0a120f1509be36e25c916
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <d639102f4cbd4cb65d1225dba3b9265596aab586
- Affected versionversion=163a203ddb36c36d4a1c942aececda0cc8d06aa7 <ffeb72a80a82aba59a6774b0611f792e0ed3b0b7
- Affected versionversion=3.12
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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Public exploit references
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