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ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL

Type: advisorySource: Official CVE List1 source record

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

Announced Source revision 1
Original source ↗

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
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