Executive brief
A vulnerability was identified in the Linux kernel's HFS+ file system driver, which is used to read and write disks formatted for Apple computers. An error in how the system manages memory when extending files could allow a local user to cause a system crash (kernel panic) or potentially access sensitive information from the computer's memory. This issue primarily affects systems that mount or interact with HFS+ formatted storage media.
Technical details
An uninitialized value vulnerability was discovered in the HFS+ file system component of the Linux kernel, specifically within the __hfsplus_ext_cache_extent() function. The issue, detected by KMSAN (Kernel Memory Sanitizer) via syzbot, occurs during file extension operations (hfsplus_file_extend). When the kernel attempts to cache extents, it may access memory that was allocated but not properly initialized in hfsplus_find_init(). A local attacker with the ability to perform write operations on an HFS+ filesystem could trigger this flaw to cause a kernel panic (Denial of Service) or potentially leak sensitive kernel memory. Patches have been merged into the Linux stable tree across multiple versions.
Affected products
- Linux Linux Kernel versions prior to 6.12-rc5
Timeline
- 2025-08-18: disclosed: Initial report by syzbot and patch authored by Viacheslav Dubeyko
- 2025-10-29: patched: Patch committed to stable tree by Greg Kroah-Hartman
- 2025-12-04: advisory: CVE published to NVD
References
- https://git.kernel.org/stable/c/14c673a2f3ecf650b694a52a88688f1d71849899
- https://git.kernel.org/stable/c/4840ceadef4290c56cc422f0fc697655f3cbf070
- https://git.kernel.org/stable/c/99202d94909d323a30d154ab0261c0a07166daec
- https://git.kernel.org/stable/c/a5bfb13b4f406aef1a450f99d22d3e48df01528c
- https://git.kernel.org/stable/c/b8a72692aa42b7dcd179a96b90bc2763ac74576a
- https://git.kernel.org/stable/c/c135b8dca65526aa5b8814e9954e0ae317d9c598
- https://git.kernel.org/stable/c/c1ec90bed504640a42bb20a5f413be39cd17ad71