CVE-2025-71150 (GCVE-0-2025-71150)
Vulnerability from cvelistv5
Published
2026-01-23 14:15
Modified
2026-08-05 12:12
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix refcount leak when invalid session is found on session lookup When a session is found but its state is not SMB2_SESSION_VALID, It indicates that no valid session was found, but it is missing to decrement the reference count acquired by the session lookup, which results in a reference count leak. This patch fixes the issue by explicitly calling ksmbd_user_session_put to release the reference to the session.
References
Impacted products
Vendor Product Version
Linux Linux Version: 2107ab40629aeabbec369cf34b8cf0f288c3eb1b
Version: 37a0e2b362b3150317fb6e2139de67b1e29ae5ff
Version: 450a844c045ff0895d41b05a1cbe8febd1acfcfd
Version: a39e31e22a535d47b14656a7d6a893c7f6cf758c
Version: b95629435b84b9ecc0c765995204a4d8a913ed52
Version: b95629435b84b9ecc0c765995204a4d8a913ed52
Version: 5.15.176   ≤
Version: 6.1.121   ≤
Version: 6.6.67   ≤
Version: 6.12.6   ≤
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{
  "containers": {
    "cna": {
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          "defaultStatus": "unaffected",
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          "programFiles": [
            "fs/smb/server/mgmt/user_session.c"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: Fix refcount leak when invalid session is found on session lookup\n\nWhen a session is found but its state is not SMB2_SESSION_VALID, It\nindicates that no valid session was found, but it is missing to decrement\nthe reference count acquired by the session lookup, which results in\na reference count leak. This patch fixes the issue by explicitly calling\nksmbd_user_session_put to release the reference to the session."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd processes attacker-controlled SMB packets over TCP, normally port 445, and the vulnerable lookup is reachable through an SMB3 transform packet.\nAC:L - An attacker controls the complete sequence: negotiate SMB3, create an invalid session, then submit a forged transform header containing its SessionId. No race, encryption key, or external condition is required.\nPR:N - SESSION_SETUP creates and publishes the session before authentication completes, and transform-header processing reaches the lookup before authentication, signing, or cryptographic verification.\nUI:N - Exploitation requires only attacker-generated network traffic and no action by a victim user.\nS:U - The resource leak and resulting denial of service affect the kernel and host managed by the same security authority as the vulnerable SMB server.\nC:N - The flaw retains session objects but does not expose their contents or provide an out-of-bounds read, use-after-free, or other disclosure primitive.\nI:N - The erroneous operation is an increment of the session\u0027s own reference count; it does not corrupt adjacent memory or provide an attacker-controlled write or code-execution primitive.\nA:H - An unauthenticated attacker can create unlimited invalid sessions and make each permanently unreclaimable, retaining multiple kernel allocations and session IDs. Repetition can exhaust kernel memory, render ksmbd or the host unavailable, and potentially cause OOM termination or a system crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:12:21.985Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/11fe566b442e3bc2774191740fd377739a87a1c0"
        },
        {
          "url": "https://git.kernel.org/stable/c/0fb87b28cafae71e9c8248432cc3a6a1fd759efc"
        },
        {
          "url": "https://git.kernel.org/stable/c/e54fb2a4772545701766cba08aab20de5eace8cd"
        },
        {
          "url": "https://git.kernel.org/stable/c/02e06785e85b4bd86ef3d23b7c8d87acc76773d5"
        },
        {
          "url": "https://git.kernel.org/stable/c/8cabcb4dd3dc85dd83a37d26efcc59a66a4074d7"
        },
        {
          "url": "https://git.kernel.org/stable/c/cafb57f7bdd57abba87725eb4e82bbdca4959644"
        }
      ],
      "title": "ksmbd: Fix refcount leak when invalid session is found on session lookup",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-71150",
    "datePublished": "2026-01-23T14:15:16.898Z",
    "dateReserved": "2026-01-13T15:30:19.662Z",
    "dateUpdated": "2026-08-05T12:12:21.985Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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