FKIE_CVE-2026-31476

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-04-23 16:17
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: do not expire session on binding failure When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS). Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6
Impacted products
Vendor Product Version
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: do not expire session on binding failure\n\nWhen a multichannel session binding request fails (e.g. wrong password),\nthe error path unconditionally sets sess-\u003estate = SMB2_SESSION_EXPIRED.\nHowever, during binding, sess points to the target session looked up via\nksmbd_session_lookup_slowpath() -- which belongs to another connection\u0027s\nuser. This allows a remote attacker to invalidate any active session by\nsimply sending a binding request with a wrong password (DoS).\n\nFix this by skipping session expiration when the failed request was\na binding attempt, since the session does not belong to the current\nconnection. The reference taken by ksmbd_session_lookup_slowpath() is\nstill correctly released via ksmbd_user_session_put()."
    }
  ],
  "id": "CVE-2026-31476",
  "lastModified": "2026-04-23T16:17:41.280",
  "metrics": {},
  "published": "2026-04-22T14:16:44.337",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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