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

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-19 16:38
VLAI
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
References
Impacted products
Vendor Product Version CPE status
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)
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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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          "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."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:38:25.036Z",
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        {
          "url": "https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66"
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    "cveId": "CVE-2026-74522",
    "datePublished": "2026-08-15T12:27:39.945Z",
    "dateReserved": "2026-08-15T05:44:03.911Z",
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      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ksmbd: fix use-after-free in __close_file_table_ids()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74522.json",
      "version": "1"
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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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/smb/server/vfs_cache.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"19bfd90d5aaf63217735d81964585c5306158e5f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"9be4a66f019ea90bd9deca70511f4f9ffebf5c6f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"cffbdc86393b0235383a20c8c59bc32f16036459\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8510a043d334ecdf83d4604782f288db6bf21d60\",\"lessThan\":\"e7188199eff46a636f3436356f0aae039be6dd66\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"df30cbfd3d8a70e61ce59f63ce5ed2261799ac10\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"aaf1d5ebb358f546414965b39da90107a7ca7ce5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5.15.38\",\"lessThan\":\"5.16\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.17.6\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/smb/server/vfs_cache.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.18\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.151\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.103\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.44\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.8\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/19bfd90d5aaf63217735d81964585c5306158e5f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9be4a66f019ea90bd9deca70511f4f9ffebf5c6f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cffbdc86393b0235383a20c8c59bc32f16036459\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T19:39:42+00:00",
      "cve": "CVE-2026-74522",
      "id": "CVE-2026-74522",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix use-after-free in __close_file_table_ids()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74522.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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