CVE-2026-72164
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the OCFS2 filesystem has a bug in ocfs2_move_extent that can cause moving data to occupied clusters. During block group scanning, if no free run is found, phys_cpos remains unchanged, potentially leading to overwriting data belonging to another inode.
Risk Assessment
This can lead to data corruption in the OCFS2 filesystem, potentially resulting in loss of data integrity and potential failure of services using this filesystem.
Recommendation
It is recommended to apply the patch that clears phys_cpos before scanning and correctly calculates the start of the free run, and update the kernel to a version with the fix.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: ocfs2: avoid moving extents to occupied clusters For non-auto OCFS2_IOC_MOVE_EXT operations, userspace supplies a physical me_goal. ocfs2_move_extent() initializes new_phys_cpos from that goal and expects ocfs2_probe_alloc_group() to replace it with a free run in the target block group. The probe currently leaves *phys_cpos unchanged if the scan reaches the end of the group without finding a free run. An occupied goal at the last bit can therefore survive the probe and be passed to __ocfs2_move_extent(), which copies file data into a cluster still owned by another inode before the bitmap is updated. When the probe does find a free run, it also subtracts move_len from the ending bit. The start of an N-bit run ending at i is i - N + 1, so the current calculation can report the bit immediately before the free run. Clear *phys_cpos before scanning and use the correct free-run start. Callers already treat a zero result as -ENOSPC, so failed probes no longer continue with an occupied caller-controlled goal.