Vulnerability-Lookup

GHSA-R5JM-2247-F5R8

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-19 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free in __close_file_table_ids()

A ksmbd_file can remain alive after logical close while another session holds a temporary reference obtained through ksmbd_lookup_fd_inode(). ksmbd_close_fd() currently marks the file closed and drops the idr-owned reference, but leaves the pointer published in the closing session's idr until the final reference is dropped.

If the foreign holder performs the final ksmbd_fd_put(), __put_fd_final() supplies the foreign session's file table to __ksmbd_close_fd(). The object is then freed without being removed from its owner's idr, and the owner session later dereferences the stale pointer during file-table teardown.

Remove the volatile id from the owner's idr while ksmbd_close_fd() still holds that table's lock, and clear volatile_id before dropping the idr-owned reference. A later foreign final put then only performs physical destruction and cannot remove the object from the wrong table.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74522"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:17:57Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in __close_file_table_ids()\n\nA ksmbd_file can remain alive after logical close while another session\nholds a temporary reference obtained through ksmbd_lookup_fd_inode().\nksmbd_close_fd() currently marks the file closed and drops the idr-owned\nreference, but leaves the pointer published in the closing session\u0027s idr\nuntil the final reference is dropped.\n\nIf the foreign holder performs the final ksmbd_fd_put(), __put_fd_final()\nsupplies the foreign session\u0027s file table to __ksmbd_close_fd(). The object\nis then freed without being removed from its owner\u0027s idr, and the owner\nsession later dereferences the stale pointer during file-table teardown.\n\nRemove the volatile id from the owner\u0027s idr while ksmbd_close_fd() still\nholds that table\u0027s lock, and clear volatile_id before dropping\nthe idr-owned reference. A later foreign final put then only performs\nphysical destruction and cannot remove the object from the wrong table.",
  "id": "GHSA-r5jm-2247-f5r8",
  "modified": "2026-08-19T18:32:29Z",
  "published": "2026-08-15T15:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74522"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/19bfd90d5aaf63217735d81964585c5306158e5f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9be4a66f019ea90bd9deca70511f4f9ffebf5c6f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cffbdc86393b0235383a20c8c59bc32f16036459"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-74522 (GCVE-0-2026-74522)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-19 16:38

Title

ksmbd: fix use-after-free in __close_file_table_ids()

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in __close_file_table_ids() A ksmbd_file can remain alive after logical close while another session holds a temporary reference obtained through ksmbd_lookup_fd_inode(). ksmbd_close_fd() currently marks the file closed and drops the idr-owned reference, but leaves the pointer published in the closing session's idr until the final reference is dropped. If the foreign holder performs the final ksmbd_fd_put(), __put_fd_final() supplies the foreign session's file table to __ksmbd_close_fd(). The object is then freed without being removed from its owner's idr, and the owner session later dereferences the stale pointer during file-table teardown. Remove the volatile id from the owner's idr while ksmbd_close_fd() still holds that table's lock, and clear volatile_id before dropping the idr-owned reference. A later foreign final put then only performs physical destruction and cannot remove the object from the wrong table.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/19bfd90d5aaf63217…
https://git.kernel.org/stable/c/67aaec2a1fdce3e1d…
https://git.kernel.org/stable/c/0c3918c2cee62ec6c…
https://git.kernel.org/stable/c/9be4a66f019ea90bd…
https://git.kernel.org/stable/c/cffbdc86393b02353…
https://git.kernel.org/stable/c/e7188199eff46a636…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < 19bfd90d5aaf63217735d81964585c5306158e5f (git) Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < 67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd (git) Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < 0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac (git) Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < 9be4a66f019ea90bd9deca70511f4f9ffebf5c6f (git) Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < cffbdc86393b0235383a20c8c59bc32f16036459 (git) Affected: 8510a043d334ecdf83d4604782f288db6bf21d60 , < e7188199eff46a636f3436356f0aae039be6dd66 (git) Affected: df30cbfd3d8a70e61ce59f63ce5ed2261799ac10 (git) Affected: aaf1d5ebb358f546414965b39da90107a7ca7ce5 (git) Affected: 5.15.38 , < 5.16 (semver) Affected: 5.17.6 , < 5.18 (semver)
Linux	Linux	Affected: 5.18 Unaffected: 0 , < 5.18 (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.151 , ≤ 6.6.* (semver) Unaffected: 6.12.103 , ≤ 6.12.* (semver) Unaffected: 6.18.44 , ≤ 6.18.* (semver) Unaffected: 7.1.8 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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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",
          "versions": [
            {
              "lessThan": "19bfd90d5aaf63217735d81964585c5306158e5f",
              "status": "affected",
              "version": "8510a043d334ecdf83d4604782f288db6bf21d60",
              "versionType": "git"
            },
            {
              "lessThan": "67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd",
              "status": "affected",
              "version": "8510a043d334ecdf83d4604782f288db6bf21d60",
              "versionType": "git"
            },
            {
              "lessThan": "0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac",
              "status": "affected",
              "version": "8510a043d334ecdf83d4604782f288db6bf21d60",
              "versionType": "git"
            },
            {
              "lessThan": "9be4a66f019ea90bd9deca70511f4f9ffebf5c6f",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "cffbdc86393b0235383a20c8c59bc32f16036459",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "e7188199eff46a636f3436356f0aae039be6dd66",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "df30cbfd3d8a70e61ce59f63ce5ed2261799ac10",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "aaf1d5ebb358f546414965b39da90107a7ca7ce5",
              "versionType": "git"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.38",
              "versionType": "semver"
            },
            {
              "lessThan": "5.18",
              "status": "affected",
              "version": "5.17.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "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": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.18",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.44",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.15.38",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.17.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in __close_file_table_ids()\n\nA ksmbd_file can remain alive after logical close while another session\nholds a temporary reference obtained through ksmbd_lookup_fd_inode().\nksmbd_close_fd() currently marks the file closed and drops the idr-owned\nreference, but leaves the pointer published in the closing session\u0027s idr\nuntil the final reference is dropped.\n\nIf the foreign holder performs the final ksmbd_fd_put(), __put_fd_final()\nsupplies the foreign session\u0027s file table to __ksmbd_close_fd(). The object\nis then freed without being removed from its owner\u0027s idr, and the owner\nsession later dereferences the stale pointer during file-table teardown.\n\nRemove the volatile id from the owner\u0027s idr while ksmbd_close_fd() still\nholds that table\u0027s lock, and clear volatile_id before dropping\nthe idr-owned reference. A later foreign final put then only performs\nphysical destruction and cannot remove the object from the wrong table."
        }
      ],
      "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 - The bug is in ksmbd, the in-kernel SMB server reached remotely over TCP port 445 via SMB2 CREATE/CLOSE/SET_INFO rename and session teardown requests.\nAC:L - An attacker controls both sides of the race by issuing concurrent SMB2 CLOSE and rename operations on the same share, then logoff or disconnect; no victim-dependent timing or memory layout is required.\nPR:L - Exploitation requires a valid authenticated SMB session and share access to open, close, and rename files; it is not reachable on pre-authentication negotiate/echo paths.\nUI:N - No end-user action is required beyond the attacker driving SMB protocol operations on their own client connection(s).\nS:U - Impact is confined to kernel memory corruption and privilege escalation on the SMB server host; it does not cross a VM, container, or IOMMU security boundary.\nC:H - Use-after-free of a freed ksmbd_file slab object during session file-table teardown enables reading attacker-influenced heap contents and building arbitrary kernel memory read primitives.\nI:H - The UAF corrupts kernel heap metadata and ksmbd_file fields (pointers, list heads), enabling heap grooming and arbitrary write or control-flow hijack for code execution as root.\nA:H - The stale IDR entry is dereferenced during __close_file_table_ids() on logoff, tree disconnect, or connection teardown, causing kernel oops/panic and repeatable remote denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:38:25.036Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/19bfd90d5aaf63217735d81964585c5306158e5f"
        },
        {
          "url": "https://git.kernel.org/stable/c/67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd"
        },
        {
          "url": "https://git.kernel.org/stable/c/0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac"
        },
        {
          "url": "https://git.kernel.org/stable/c/9be4a66f019ea90bd9deca70511f4f9ffebf5c6f"
        },
        {
          "url": "https://git.kernel.org/stable/c/cffbdc86393b0235383a20c8c59bc32f16036459"
        },
        {
          "url": "https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66"
        }
      ],
      "title": "ksmbd: fix use-after-free in __close_file_table_ids()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74522",
    "datePublished": "2026-08-15T12:27:39.945Z",
    "dateReserved": "2026-08-15T05:44:03.911Z",
    "dateUpdated": "2026-08-19T16:38:25.036Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-R5JM-2247-F5R8

CVE-2026-74522 (GCVE-0-2026-74522)

Tags

Sightings

Nomenclature