In the Linux kernel, the XFS filesystem flaw causes the reflink flag to be incorrectly transferred during mapping exchanges. When two files are exchanged, the flag that indicates shared blocks is moved in a way that leaves the receiving inode without the flag. Subsequent writes to blocks that should trigger copy‑on‑write are performed in place, corrupting data in the other file. A similar issue exists for the XFS_IOC_SWAPEXT ioctl, which moves the reflink flag without ensuring the destination inode has been prepared to use it. The result is unintended data corruption or loss in files that share blocks, undermining file integrity.

The flaw is present in all Linux kernel builds that contain the XFS filesystem logic; any kernel that ships XFS is potentially vulnerable, regardless of distribution. No specific version or distribution is named in the data, so the scope is broad across all current and historic Linux kernels with XFS support.

The CVSS score of 7.8 indicates a high severity vulnerability, but the EPSS score of less than 1 % reflects a very low exploitation probability. The flaw does not provide a remote exploitation surface; it requires privileged local access to trigger a mapping exchange or call XFS_IOC_SWAPEXT. Because the exploitation path involves privileged operations, the risk is moderate to high for systems that rely on XFS for critical data. The absence of a KEV listing means no confirmed exploitation yet, yet the potential for data loss warrants prompt mitigation.