ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on conn->async_requests via setup_async_work(), with cancel_fn = smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock. When the request is cancelled, the worker frees the file_lock with locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never reaches release_async_work() -- the only site that unlinks the work from conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays matchable on async_requests with a live cancel_fn pointing at the freed file_lock, until connection teardown finally runs release_async_work(). smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free: BUG: KASAN: slab-use-after-free in __locks_delete_block __locks_delete_block locks_delete_block ksmbd_vfs_posix_lock_unblock smb2_remove_blocked_lock smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn handle_ksmbd_work Allocated by ...: locks_alloc_lock <- smb2_lock Freed by ...: locks_free_lock <- smb2_lock (cancelled branch) ... cache file_lock_cache of size 192 Reproduced on mainline with KASAN by an authenticated SMB client. Skip a work whose state is already KSMBD_W
CVE-2026-53198
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-53198
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "b7063c7426ea5a4d15e01b60538718765392f49d",
"versionType": "git"
},
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd",
"versionType": "git"
},
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "89ae9df09d2c1fb4a4eb495c113a7ce1dca34147",
"versionType": "git"
},
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "14d2eee0193ac3cd1bf3d014373449f0b8d35d6d",
"versionType": "git"
},
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694",
"versionType": "git"
},
{
"status": "affected",
"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
"lessThan": "f580d27e8928828693df44ba2db0fffdbe11dfea",
"versionType": "git"
}
],
"programFiles": [
"fs/smb/server/smb2pdu.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.176",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.94",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.36",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.13",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/smb/server/smb2pdu.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-53198
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #28436 · Revision 1
- Added to Heist Feed
- Publisher date