The Linux kernel’s HPFS file system code incorrectly handles block sizes larger than PAGE_SIZE in buffer_heads, which triggers a BUG_ON in folio_set_bh during the first __bread_gfp call. This results in a kernel panic that immediately aborts the system. The vulnerability has a CVSS v3.1 score of 5.5, indicating a moderate severity and an impact limited to system availability. It does not cause data corruption or information disclosure but can be exploited by mounting a specially crafted HPFS volume to force a crash. The weakness is associated with CWE-617 (Use After Free).

All installations of the Linux kernel that do not include the commit that fixes the bug are vulnerable. The advisory lists only the Linux kernel as a vendor and does not provide a specific version range, so the issue applies to every kernel release prior to the patch commit. Distribution maintainers generally backport the fix in subsequent kernel updates.

The bug is exploitable via mounting an HPFS filesystem with an oversized block size. This typically requires local access to mount the filesystem or elevated privileges to mount arbitrary devices, so the attack vector is local. The EPSS score is less than 1%, reflecting a very low probability of exploitation, and the vulnerability is not listed in the CISA KEV catalog. The CVSS score of 5.5 indicates that the impact is moderate, and while this does not provide remote code execution, it can disrupt availability by causing a kernel panic.