Executive brief
A vulnerability in the Linux kernel's HFS+ filesystem driver can cause a system crash (kernel panic). This occurs when the system encounters a corrupted filesystem or specific internal errors while managing data nodes. An attacker or a corrupted disk image could trigger this flaw to disrupt system availability.
Technical details
A vulnerability exists in the Linux kernel hfsplus driver within the hfs_bnode_create() function. When the function discovers a node is already hashed, it returns the existing node without incrementing its reference count. This leads to a reference count inconsistency; subsequently, when hfs_bnode_put() is called to free the node, it triggers a BUG_ON() check because the reference count is zero, resulting in a kernel panic. This condition can be triggered by filesystem corruption or specific allocation failures in hfs_bmap_alloc(). The fix ensures the function returns an error pointer (-EEXIST) instead of the improperly referenced node.
Affected products
- Linux Linux kernel hfsplus driver
Timeline
- 2025-12-30: patched: Initial patch authored
- 2026-05-27: disclosed: CVE published
References
- https://git.kernel.org/stable/c/1ca428769cb4737a25bd32fb4d1573cc09eeaeef
- https://git.kernel.org/stable/c/2e6ff6a6fc69cc17ed10c9cb6242935d52acd52d
- https://git.kernel.org/stable/c/2e9185a42e0e237c74435fd092b7c34537c62156
- https://git.kernel.org/stable/c/507a1de58c21c95ad7c44afccaf1222d1c42246b
- https://git.kernel.org/stable/c/51838112d9c22502333c3085ca0c0d691e7093c6
- https://git.kernel.org/stable/c/7b57ada854b32310f224abd61bcfec2d5790ff0a
- https://git.kernel.org/stable/c/986455135b95f32c1f142068e451098fc751749e