CVE-2025-38728 smb3: fix for slab out of bounds on mount to ksmbd
A slab out-of-bounds read in the Linux kernel CIFS module during mount operations can cause a system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38728?
CVE-2025-38728 is a critical memory corruption vulnerability in Debian Debian Linux, published on 4 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smb3: fix for slab out of bounds on mount to ksmbd
With KASAN enabled, it is possible to get a slab out of bounds during mount to ksmbd due to missing check in parse_server_interfaces() (see below):
BUG: KASAN: slab-out-of-bounds in parse_server_interfaces+0x14ee/0x1880 [cifs] Read of size 4 at addr ffff8881433dba98 by task mount/9827
CPU: 5 UID: 0 PID: 9827 Comm: mount Tainted: G OE 6.16.0-rc2-kasan #2 PREEMPT(voluntary) Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.13.1 06/14/2019 Call Trace: <TASK> dump_stack_lvl+0x9f/0xf0 print_report+0xd1/0x670 __virt_addr_valid+0x22c/0x430 ? parse_server_interfaces+0x14ee/0x1880 [cifs] ? kasan_complete_mode_report_info+0x2a/0x1f0 ? parse_server_interfaces+0x14ee/0x1880 [cifs] kasan_report+0xd6/0x110 parse_server_interfaces+0x14ee/0x1880 [cifs] __asan_report_load_n_noabort+0x13/0x20 parse_server_interfaces+0x14ee/0x1880 [cifs] ? __pfx_parse_server_interfaces+0x10/0x10 [cifs] ? trace_hardirqs_on+0x51/0x60 SMB3_request_interfaces+0x1ad/0x3f0 [cifs] ? __pfx_SMB3_request_interfaces+0x10/0x10 [cifs] ? SMB2_tcon+0x23c/0x15d0 [cifs] smb3_qfs_tcon+0x173/0x2b0 [cifs] ? __pfx_smb3_qfs_tcon+0x10/0x10 [cifs] ? cifs_get_tcon+0x105d/0x2120 [cifs] ? do_raw_spin_unlock+0x5d/0x200 ? cifs_get_tcon+0x105d/0x2120 [cifs] ? __pfx_smb3_qfs_tcon+0x10/0x10 [cifs] cifs_mount_get_tcon+0x369/0xb90 [cifs] ? dfs_cache_find+0xe7/0x150 [cifs] dfs_mount_share+0x985/0x2970 [cifs] ? check_path.constprop.0+0x28/0x50 ? save_trace+0x54/0x370 ? __pfx_dfs_mount_share+0x10/0x10 [cifs] ? __lock_acquire+0xb82/0x2ba0 ? __kasan_check_write+0x18/0x20 cifs_mount+0xbc/0x9e0 [cifs] ? __pfx_cifs_mount+0x10/0x10 [cifs] ? do_raw_spin_unlock+0x5d/0x200 ? cifs_setup_cifs_sb+0x29d/0x810 [cifs] cifs_smb3_do_mount+0x263/0x1990 [cifs]
Weakness: CWE-125
Which versions are affected by CVE-2025-38728?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38728?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-38728 being exploited?
There is no known exploitation of CVE-2025-38728 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-66875, AZL-73845, BELL-CVE-2025-38728, DEBIAN-CVE-2025-38728, GHSA-p6j9-xx79-r863, ROOT-OS-DEBIAN-11-CVE-2025-38728 and 3 more.