{"id":"CVE-2025-40320","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix potential cfid UAF in smb2_query_info_compound\n\nWhen smb2_query_info_compound() retries, a previously allocated cfid may\nhave been freed in the first a…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix potential cfid UAF in smb2_query_info_compound\n\nWhen smb2_query_info_compound() retries, a previously allocated cfid may\nhave been freed in the first a…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","published":"2025-12-08","updated":"2026-10-14","sourceUpdated":"2026-10-14T22:10:00.210","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-40320","references":[{"url":"https://git.kernel.org/stable/c/327f89c21601ebb7889f8c97754b76f08ce95a0c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5c76f9961c170552c1d07c830b5e145475151600","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/939c4e33005e2a56ea8fcedddf0da92df864bd3b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b556c278d43f4707a9073ca74d55581b4f279806","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00418,"epssPercentile":0.34513,"ingestedAt":"2026-10-14T23:00:02.024Z","slug":"CVE-2025-40320","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix potential cfid UAF in smb2_query_info_compound\n\nWhen smb2_query_info_compound() retries, a previously allocated cfid may\nhave been freed in the first attempt.\nBecause cfid wasn't reset on replay, later cleanup could act on a stale\npointer, leading to a potential use-after-free.\n\nReinitialize cfid to NULL under the replay label.\n\nExample trace (trimmed):\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 1 PID: 11224 at ../lib/refcount.c:28 refcount_warn_saturate+0x9c/0x110\n[...]\nRIP: 0010:refcount_warn_saturate+0x9c/0x110\n[...]\nCall Trace:\n <TASK>\n smb2_query_info_compound+0x29c/0x5c0 [cifs f90b72658819bd21c94769b6a652029a07a7172f]\n ? step_into+0x10d/0x690\n ? __legitimize_path+0x28/0x60\n smb2_queryfs+0x6a/0xf0 [cifs f90b72658819bd21c94769b6a652029a07a7172f]\n smb311_queryfs+0x12d/0x140 [cifs f90b72658819bd21c94769b6a652029a07a7172f]\n ? kmem_cache_alloc+0x18a/0x340\n ? getname_flags+0x46/0x1e0\n cifs_statfs+0x9f/0x2b0 [cifs f90b72658819bd21c94769b6a652029a07a7172f]\n statfs_by_dentry+0x67/0x90\n vfs_statfs+0x16/0xd0\n user_statfs+0x54/0xa0\n __do_sys_statfs+0x20/0x50\n do_syscall_64+0x58/0x80\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}