CVE-2025-40351 hfsplus: fix KMSAN uninit-value issue in hfsplus_delete_cat()
A local attacker can trigger an uninitialized value bug in the HFS+ filesystem driver, potentially leaking kernel memory contents.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40351?
CVE-2025-40351 is a vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
hfsplus: fix KMSAN uninit-value issue in hfsplus_delete_cat()
The syzbot reported issue in hfsplus_delete_cat():
[ 70.682285][ T9333] ===================================================== [ 70.682943][ T9333] BUG: KMSAN: uninit-value in hfsplus_subfolders_dec+0x1d7/0x220 [ 70.683640][ T9333] hfsplus_subfolders_dec+0x1d7/0x220 [ 70.684141][ T9333] hfsplus_delete_cat+0x105d/0x12b0 [ 70.684621][ T9333] hfsplus_rmdir+0x13d/0x310 [ 70.685048][ T9333] vfs_rmdir+0x5ba/0x810 [ 70.685447][ T9333] do_rmdir+0x964/0xea0 [ 70.685833][ T9333] __x64_sys_rmdir+0x71/0xb0 [ 70.686260][ T9333] x64_sys_call+0xcd8/0x3cf0 [ 70.686695][ T9333] do_syscall_64+0xd9/0x1d0 [ 70.687119][ T9333] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 70.687646][ T9333] [ 70.687856][ T9333] Uninit was stored to memory at: [ 70.688311][ T9333] hfsplus_subfolders_inc+0x1c2/0x1d0 [ 70.688779][ T9333] hfsplus_create_cat+0x148e/0x1800 [ 70.689231][ T9333] hfsplus_mknod+0x27f/0x600 [ 70.689730][ T9333] hfsplus_mkdir+0x5a/0x70 [ 70.690146][ T9333] vfs_mkdir+0x483/0x7a0 [ 70.690545][ T9333] do_mkdirat+0x3f2/0xd30 [ 70.690944][ T9333] __x64_sys_mkdir+0x9a/0xf0 [ 70.691380][ T9333] x64_sys_call+0x2f89/0x3cf0 [ 70.691816][ T9333] do_syscall_64+0xd9/0x1d0 [ 70.692229][ T9333] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 70.692773][ T9333] [ 70.692990][ T9333] Uninit was stored to memory at: [ 70.693469][ T9333] hfsplus_subfolders_inc+0x1c2/0x1d0 [ 70.693960][ T9333] hfsplus_create_cat+0x148e/0x1800 [ 70.694438][ T9333] hfsplus_fill_super+0x21c1/0x2700 [ 70.694911][ T9333] mount_bdev+0x37b/0x530 [ 70.695320][ T9333] hfsplus_mount+0x4d/0x60 [ 70.695729][ T9333] legacy_get_tree+0x113/0x2c0 [ 70.696167][ T9333] vfs_get_tree+0xb3/0x5c0 [ 70.696588][ T9333] do_new_mount+0x73e/0x1630 [ 70.697013][ T9333] path_mount+0x6e3/0x1eb0 [ 70.697425][ T9333] __se_sys_mount+0x733/0x830 [ 70.697857][ T9333] __x64_sys_mount+0xe4/0x150 [ 70.698269][ T9333] x64_sys_call+0x2691/0x3cf0 [ 70.698704][ T9333] do_syscall_64+0xd9/0x1d0 [ 70.699117][ T9333] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 70.699730][ T9333] [ 70.699946][ T9333] Uninit was created at: [ 70.700378][ T9333] __alloc_pages_noprof+0x714/0xe60 [ 70.700843][ T9333] alloc_pages_mpol_noprof+0x2a2/0x9b0 [ 70.701331][ T9333] alloc_pages_noprof+0xf8/0x1f0 [ 70.701774][ T9333] allocate_slab+0x30e/0x1390 [ 70.702194][ T9333] ___slab_alloc+0x1049/0x33a0 [ 70.702635][ T9333] kmem_cache_alloc_lru_noprof+0x5ce/0xb20 [ 70.703153][ T9333] hfsplus_alloc_inode+0x5a/0xd0 [ 70.703598][ T9333] alloc_inode+0x82/0x490 [ 70.703984][ T9333] iget_locked+0x22e/0x1320 [ 70.704428][ T9333] hfsplus_iget+0x5c/0xba0 [ 70.704827][ T9333] hfsplus_btree_open+0x135/0x1dd0 [ 70.705291][ T9333] hfsplus_fill_super+0x1132/0x2700 [ 70.705776][ T9333] mount_bdev+0x37b/0x530 [ 70.706171][ T9333] hfsplus_mount+0x4d/0x60 [ 70.706579][ T9333] legacy_get_tree+0x113/0x2c0 [ 70.707019][ T9333] vfs_get_tree+0xb3/0x5c0 [ 70.707444][ T9333] do_new_mount+0x73e/0x1630 [ 70.707865][ T9333] path_mount+0x6e3/0x1eb0 [ 70.708270][ T9333] __se_sys_mount+0x733/0x830 [ 70.708711][ T9333] __x64_sys_mount+0xe4/0x150 [ 70.709158][ T9333] x64_sys_call+0x2691/0x3cf0 [ 70.709630][ T9333] do_syscall_64+0xd9/0x1d0 [ 70.710053][ T9333] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 70.710611][ T9333] [ 70.710842][ T9333] CPU: 3 UID: 0 PID: 9333 Comm: repro Not tainted 6.12.0-rc6-dirty #17 [ 70.711568][ T9333] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 70.712490][ T9333] ===================================================== [ 70.713085][ T9333] Disabling lock debugging due to kernel taint [ 70.713618][ T9333] Kernel panic - not syncing: kmsan.panic set ... [ 70.714159][ T9333] ---truncated---
Which versions are affected by CVE-2025-40351?
How do I fix CVE-2025-40351?
Apply the vendor's patch.
Is CVE-2025-40351 being exploited?
There is no known exploitation of CVE-2025-40351 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40351, DEBIAN-CVE-2025-40351, GHSA-fw59-rp53-2wvr, ROOT-OS-UBUNTU-2404-CVE-2025-40351, UBUNTU-CVE-2025-40351.