Executive brief
A vulnerability in the Btrfs file system of the Linux kernel can lead to data loss after a power failure or system crash. When certain file operations occur—specifically involving the deletion and replacement of directories—the system may fail to properly record new files or folders to the permanent storage log. Consequently, even if a user manually saves their changes, those changes might disappear if the system loses power before a full background synchronization occurs.
Technical details
A vulnerability exists in the Btrfs tree-log component where logging a parent directory of a conflicting inode fails to include new dentries. When a directory is deleted and replaced by a file with the same name, and a subsequent fsync is performed on a related path, the parent directory is marked as logged without its new entries being recorded. This causes subsequent explicit fsync calls on the parent directory to be treated as no-ops. If a power failure occurs before the transaction is committed to disk, the missing dentries are not recovered during log replay. The issue has been patched in multiple stable branches of the Linux kernel.
Affected products
- Linux Linux Kernel 5.1 to 6.6.130, 6.7 to 6.12.78, 6.13 to 6.18.20, 6.19 to 6.19.10, 7.0-rc1 to 7.0-rc4
Timeline
- 2026-03-03: other: Patch authored
- 2026-04-03: disclosed: CVE published
- 2026-05-20: advisory: NVD last modified with full analysis
References
- https://git.kernel.org/stable/c/1cf30c73602c69d750c9345c47f2c0e9d0cfb578
- https://git.kernel.org/stable/c/56e72c8b02d982be775d9df025357c152383ee84
- https://git.kernel.org/stable/c/6f5a51969b1deb79aefd2194b48fe7e78e72ff7e
- https://git.kernel.org/stable/c/9573a365ff9ff45da9222d3fe63695ce562beb24
- https://git.kernel.org/stable/c/f556b1e09d054e31f464c0fd37280c2b5a393fee