CVE-2026-90169 (GCVE-0-2026-90169)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-09-17 16:06
VLAI
Title
ksmbd: free preauth sessions on connection teardown
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: free preauth sessions on connection teardown SMB3.1.1 multichannel binding preserves the preauthentication hash in a preauth_session between the NTLM negotiate and authenticate requests. The binding NTLM negotiate allocates this object and returns STATUS_MORE_PROCESSING_REQUIRED. If the client disconnects before it sends the authenticate request, neither the authenticate nor error cleanup paths free the object. Release any remaining preauthentication sessions when tearing down the connection. Initialize the list when allocating the connection so that this cleanup is safe regardless of the negotiated dialect.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < effcf48d79d8aa53113d8289e140746f25ceb62c (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < b62b1ebb25f0a19067ed5b1a86036b2dc98be44f (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < a41a98ee16ae038751b6639decadaa3ce15ca18a (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < 8e2ebc77678832e981adc008d25cd8f67d08ebc4 (git)
Affected: f5a544e3bab78142207e0242d22442db85ba1eff , < 06c7b1d731bc105a8644f1b70165ba8b9416cbab (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "fs/smb/server/connection.c",
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/smb2ops.c"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: free preauth sessions on connection teardown\n\nSMB3.1.1 multichannel binding preserves the preauthentication hash in a\npreauth_session between the NTLM negotiate and authenticate requests.\nThe binding NTLM negotiate allocates this object and returns\nSTATUS_MORE_PROCESSING_REQUIRED. If the client disconnects before it sends\nthe authenticate request, neither the authenticate nor error cleanup paths\nfree the object.\n\nRelease any remaining preauthentication sessions when tearing down the\nconnection. Initialize the list when allocating the connection so that this\ncleanup is safe regardless of the negotiated dialect."
        }
      ],
      "providerMetadata": {
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        "shortName": "Linux"
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    "dateReserved": "2026-09-11T19:38:34.790Z",
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    "state": "PUBLISHED"
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      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-90169.json",
      "version": "4"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: free preauth sessions on connection teardown\n\nSMB3.1.1 multichannel binding preserves the preauthentication hash in a\npreauth_session between the NTLM negotiate and authenticate requests.\nThe binding NTLM negotiate allocates this object and returns\nSTATUS_MORE_PROCESSING_REQUIRED. If the client disconnects before it sends\nthe authenticate request, neither the authenticate nor error cleanup paths\nfree the object.\n\nRelease any remaining preauthentication sessions when tearing down the\nconnection. Initialize the list when allocating the connection so that this\ncleanup is safe regardless of the negotiated dialect."
          }
        ],
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        "metrics": {},
        "published": "2026-09-17T17:17:10.333",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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  }
}



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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.

Sightings

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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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.