CVE-2022-50372 cifs: Fix memory leak when build ntlmssp negotiate blob failed
A memory leak in the Linux kernel CIFS module during failed NTLMSSP negotiation allows attackers to exhaust system memory, causing denial of service.
- 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-2022-50372?
CVE-2022-50372 is a medium-severity denial of service vulnerability in Linux kernel, published on 17 Sep 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:
cifs: Fix memory leak when build ntlmssp negotiate blob failed
There is a memory leak when mount cifs: unreferenced object 0xffff888166059600 (size 448): comm "mount.cifs", pid 51391, jiffies 4295596373 (age 330.596s) hex dump (first 32 bytes): fe 53 4d 42 40 00 00 00 00 00 00 00 01 00 82 00 .SMB@........... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<0000000060609a61>] mempool_alloc+0xe1/0x260 [<00000000adfa6c63>] cifs_small_buf_get+0x24/0x60 [<00000000ebb404c7>] __smb2_plain_req_init+0x32/0x460 [<00000000bcf875b4>] SMB2_sess_alloc_buffer+0xa4/0x3f0 [<00000000753a2987>] SMB2_sess_auth_rawntlmssp_negotiate+0xf5/0x480 [<00000000f0c1f4f9>] SMB2_sess_setup+0x253/0x410 [<00000000a8b83303>] cifs_setup_session+0x18f/0x4c0 [<00000000854bd16d>] cifs_get_smb_ses+0xae7/0x13c0 [<000000006cbc43d9>] mount_get_conns+0x7a/0x730 [<000000005922d816>] cifs_mount+0x103/0xd10 [<00000000e33def3b>] cifs_smb3_do_mount+0x1dd/0xc90 [<0000000078034979>] smb3_get_tree+0x1d5/0x300 [<000000004371f980>] vfs_get_tree+0x41/0xf0 [<00000000b670d8a7>] path_mount+0x9b3/0xdd0 [<000000005e839a7d>] __x64_sys_mount+0x190/0x1d0 [<000000009404c3b9>] do_syscall_64+0x35/0x80
When build ntlmssp negotiate blob failed, the session setup request should be freed.
Weakness: CWE-401
Which versions are affected by CVE-2022-50372?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-50372?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2022-50372 being exploited?
There is no known exploitation of CVE-2022-50372 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-50372, GHSA-5wx2-vv79-wfg8, UBUNTU-CVE-2022-50372.