CVE-2025-37876 netfs: Only create /proc/fs/netfs with CONFIG_PROC_FS
A null pointer dereference in the Linux kernel netfs module causes a system crash when CONFIG_PROC_FS is disabled.
- 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-2025-37876?
CVE-2025-37876 is a high-severity vulnerability in Linux kernel, published on 9 May 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:
netfs: Only create /proc/fs/netfs with CONFIG_PROC_FS
When testing a special config:
CONFIG_NETFS_SUPPORTS=y CONFIG_PROC_FS=n
The system crashes with something like:
[ 3.766197] ------------[ cut here ]------------ [ 3.766484] kernel BUG at mm/mempool.c:560! [ 3.766789] Oops: invalid opcode: 0000 [#1] SMP NOPTI [ 3.767123] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W [ 3.767777] Tainted: [W]=WARN [ 3.767968] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), [ 3.768523] RIP: 0010:mempool_alloc_slab.cold+0x17/0x19 [ 3.768847] Code: 50 fe ff 58 5b 5d 41 5c 41 5d 41 5e 41 5f e9 93 95 13 00 [ 3.769977] RSP: 0018:ffffc90000013998 EFLAGS: 00010286 [ 3.770315] RAX: 000000000000002f RBX: ffff888100ba8640 RCX: 0000000000000000 [ 3.770749] RDX: 0000000000000000 RSI: 0000000000000003 RDI: 00000000ffffffff [ 3.771217] RBP: 0000000000092880 R08: 0000000000000000 R09: ffffc90000013828 [ 3.771664] R10: 0000000000000001 R11: 00000000ffffffea R12: 0000000000092cc0 [ 3.772117] R13: 0000000000000400 R14: ffff8881004b1620 R15: ffffea0004ef7e40 [ 3.772554] FS: 0000000000000000(0000) GS:ffff8881b5f3c000(0000) knlGS:0000000000000000 [ 3.773061] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3.773443] CR2: ffffffff830901b4 CR3: 0000000004296001 CR4: 0000000000770ef0 [ 3.773884] PKRU: 55555554 [ 3.774058] Call Trace: [ 3.774232] <TASK> [ 3.774371] mempool_alloc_noprof+0x6a/0x190 [ 3.774649] ? _printk+0x57/0x80 [ 3.774862] netfs_alloc_request+0x85/0x2ce [ 3.775147] netfs_readahead+0x28/0x170 [ 3.775395] read_pages+0x6c/0x350 [ 3.775623] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.775928] page_cache_ra_unbounded+0x1bd/0x2a0 [ 3.776247] filemap_get_pages+0x139/0x970 [ 3.776510] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.776820] filemap_read+0xf9/0x580 [ 3.777054] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.777368] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.777674] ? find_held_lock+0x32/0x90 [ 3.777929] ? netfs_start_io_read+0x19/0x70 [ 3.778221] ? netfs_start_io_read+0x19/0x70 [ 3.778489] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.778800] ? lock_acquired+0x1e6/0x450 [ 3.779054] ? srso_alias_return_thunk+0x5/0xfbef5 [ 3.779379] netfs_buffered_read_iter+0x57/0x80 [ 3.779670] __kernel_read+0x158/0x2c0 [ 3.779927] bprm_execve+0x300/0x7a0 [ 3.780185] kernel_execve+0x10c/0x140 [ 3.780423] ? __pfx_kernel_init+0x10/0x10 [ 3.780690] kernel_init+0xd5/0x150 [ 3.780910] ret_from_fork+0x2d/0x50 [ 3.781156] ? __pfx_kernel_init+0x10/0x10 [ 3.781414] ret_from_fork_asm+0x1a/0x30 [ 3.781677] </TASK> [ 3.781823] Modules linked in: [ 3.782065] ---[ end trace 0000000000000000 ]---
This is caused by the following error path in netfs_init():
if (!proc_mkdir("fs/netfs", NULL)) goto error_proc;
Fix this by adding ifdef in netfs_main(), so that /proc/fs/netfs is only created with CONFIG_PROC_FS.
Weakness: CWE-476
Which versions are affected by CVE-2025-37876?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37876?
Apply the vendor's patch.
Is CVE-2025-37876 being exploited?
There is no known exploitation of CVE-2025-37876 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37876, DEBIAN-CVE-2025-37876, GHSA-xp7w-6352-489g, ROOT-OS-DEBIAN-12-CVE-2025-37876, ROOT-OS-UBUNTU-2204-CVE-2025-37876, ROOT-OS-UBUNTU-2404-CVE-2025-37876 and 1 more.