CVE-2025-37952 (GCVE-0-2025-37952)
Vulnerability from cvelistv5
Published
2025-05-20 16:01
Modified
2026-08-05 11:58
Severity ?
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix UAF in __close_file_table_ids A use-after-free is possible if one thread destroys the file via __ksmbd_close_fd while another thread holds a reference to it. The existing checks on fp->refcount are not sufficient to prevent this. The fix takes ft->lock around the section which removes the file from the file table. This prevents two threads acquiring the same file pointer via __close_file_table_ids, as well as the other functions which retrieve a file from the IDR and which already use this same lock.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
Version: 0626e6641f6b467447c81dd7678a69c66f7746cf
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.29",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.14.*",
              "status": "unaffected",
              "version": "6.14.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.91",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.29",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.14.7",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: Fix UAF in __close_file_table_ids\n\nA use-after-free is possible if one thread destroys the file\nvia __ksmbd_close_fd while another thread holds a reference to\nit. The existing checks on fp-\u003erefcount are not sufficient to\nprevent this.\n\nThe fix takes ft-\u003elock around the section which removes the\nfile from the file table. This prevents two threads acquiring the\nsame file pointer via __close_file_table_ids, as well as the other\nfunctions which retrieve a file from the IDR and which already use\nthis same lock."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd is the in-kernel SMB server; the entire path is driven by SMB2 PDUs (TREE_DISCONNECT, LOGOFF, CLOSE) arriving on TCP/445 from a remote peer. No local access is involved at any point.\nAC:L - The attacker controls both sides of the race \u2014 each SMB2 request is dispatched to the concurrent \"ksmbd-io\" workqueue, so pipelining CLOSE alongside TREE_DISCONNECT/LOGOFF on one connection (or using multichannel connections sharing one file table) reliably produces overlapping execution. The unlocked IDR walk gives a wide window, and the race can be retried indefinitely.\nPR:L - The attacker must complete SMB2 SESSION_SETUP, TREE_CONNECT and open at least one file so the session file table is populated, which needs valid (low-privilege) share credentials in a default configuration. Any ordinary share user qualifies, and on guest-mapped public shares even that requirement disappears.\nUI:N - The attacker drives the entire sequence from their own SMB connection; no action by a local user or administrator is needed.\nS:U - The corruption and its consequences are confined to the kernel\u0027s own security authority; there is no VM, IOMMU or sandbox boundary crossed.\nC:H - The freed ksmbd_file is dereferenced for fp-\u003etcon, fp-\u003ef_ci and the fp-\u003eblocked_works list, and the attacker can reallocate the slab object via SMB2_CREATE to control those contents, turning the UAF into an arbitrary kernel-memory read primitive.\nI:H - set_close_state_blocked_works() performs `cancel_work-\u003estate = KSMBD_WORK_CLOSED` and then an indirect call `cancel_work-\u003ecancel_fn(cancel_work-\u003ecancel_argv)` using pointers read out of freed memory, and __ksmbd_close_fd() fput()s a stale struct file and double-frees the object \u2014 giving write-what-where and control-flow hijack primitives.\nA:H - Even unexploited, the double refcount decrement and double kmem_cache_free/fput corrupt the slab allocator and file refcounts, causing an immediate oops or panic that takes down the whole server."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:58:35.992Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fec1f9e9a650e8e7011330a085c77e7bf2a08ea9"
        },
        {
          "url": "https://git.kernel.org/stable/c/9e9841e232b51171ddf3bc4ee517d5d28dc8cad6"
        },
        {
          "url": "https://git.kernel.org/stable/c/16727e442568a46d9cca69fe2595896de86e120d"
        },
        {
          "url": "https://git.kernel.org/stable/c/36991c1ccde2d5a521577c448ffe07fcccfe104d"
        }
      ],
      "title": "ksmbd: Fix UAF in __close_file_table_ids",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37952",
    "datePublished": "2025-05-20T16:01:47.164Z",
    "dateReserved": "2025-04-16T04:51:23.973Z",
    "dateUpdated": "2026-08-05T11:58:35.992Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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