CVE-2025-37777 (GCVE-0-2025-37777)

Vulnerability from cvelistv5 – Published: 2025-05-01 13:07 – Updated: 2026-08-05 11:57
VLAI
Title
ksmbd: fix use-after-free in __smb2_lease_break_noti()
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in __smb2_lease_break_noti() Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed.
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
Linux Linux Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 1da8bd9a10ecd718692732294d15fd801c0eabb5 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 1aec4d14cf81b7b3e7b69eb1cfa94144eed7138e (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < e59796fc80603bcd8569d4d2e10b213c1918edb4 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 21a4e47578d44c6b37c4fc4aba8ed7cc8dbb13de (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.6.101 , ≤ 6.6.* (semver)
Unaffected: 6.12.26 , ≤ 6.12.* (semver)
Unaffected: 6.14.4 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in __smb2_lease_break_noti()\n\nMove tcp_transport free to ksmbd_conn_free. If ksmbd connection is\nreferenced when ksmbd server thread terminates, It will not be freed,\nbut conn-\u003etcp_transport is freed. __smb2_lease_break_noti can be performed\nasynchronously when the connection is disconnected. __smb2_lease_break_noti\ncalls ksmbd_conn_write, which can cause use-after-free\nwhen conn-\u003eksmbd_transport is already freed."
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              "value": "AV:N - ksmbd is the in-kernel SMB server listening on TCP/445, and the entire trigger sequence (CREATE with a lease context, TCP disconnect, conflicting CREATE from a second connection) is driven purely by remote SMB2 traffic. No local access is needed.\nAC:L - The attacker fully controls both sides of the race by opening two connections \u2014 one takes a lease and disconnects, the other forces the lease break \u2014 and can repeat it indefinitely until the RCU-deferred opinfo teardown overlaps the transport free. Per guidance, an attacker-created race and a use-after-free are Low.\nPR:L - Reaching `alloc_opinfo()` requires a completed SESSION_SETUP, TREE_CONNECT and SMB2 CREATE with an RqLs lease context, so an authenticated (any unprivileged share user, including guest where mapped) SMB account is needed. This matches the scoring of the sibling post-authentication ksmbd UAFs.\nUI:N - The attacker drives every step from its own SMB connections; no action by an administrator or any other client is required.\nS:U - The corruption and its consequences are confined to the kernel\u0027s own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The freed kmalloc-64 `tcp_transport` can be reclaimed with attacker-controlled data and its `ops` field is dereferenced, which combined with the indirect call yields arbitrary kernel memory disclosure; the already-released socket is also reused.\nI:H - `ksmbd_conn_write()` reads the `ops` vtable pointer out of the freed object and indirectly calls `ops-\u003ewritev`, giving a direct control-flow hijack primitive and hence arbitrary kernel code execution after heap spraying.\nA:H - Even unweaponized, dereferencing the freed transport and the released socket reliably oopses or panics the kernel, and the attacker can trigger it repeatedly to keep the server down."
            }
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    "dateReserved": "2025-04-16T04:51:23.939Z",
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If ksmbd connection is\\nreferenced when ksmbd server thread terminates, It will not be freed,\\nbut conn-\u003etcp_transport is freed. __smb2_lease_break_noti can be performed\\nasynchronously when the connection is disconnected. __smb2_lease_break_noti\\ncalls ksmbd_conn_write, which can cause use-after-free\\nwhen conn-\u003eksmbd_transport is already freed.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: se corrige el error \\\"use-after-free\\\" en __smb2_lease_break_noti(). Se mueve tcp_transport libre a ksmbd_conn_free. Si se hace referencia a la conexi\u00f3n ksmbd al finalizar el subproceso del servidor ksmbd, no se liberar\u00e1, pero s\u00ed se liberar\u00e1 conn-\u0026gt;tcp_transport. __smb2_lease_break_noti puede ejecutarse asincr\u00f3nicamente cuando se desconecta la conexi\u00f3n. __smb2_lease_break_noti llama a ksmbd_conn_write, lo que puede causar un error \\\"use-after-free\\\" cuando conn-\u0026gt;ksmbd_transport ya est\u00e1 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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-30T10:28:57+00:00",
      "cve": "CVE-2025-37777",
      "id": "CVE-2025-37777",
      "initial_release_date": "2025-05-01T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix use-after-free in __smb2_lease_break_noti()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37777.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-31T01:16:06Z",
      "cve": "CVE-2025-37777",
      "id": "CVE-2025-37777",
      "initial_release_date": "2025-05-02T02:02:32Z",
      "product_status:known_not_affected": "456",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-37777",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-37777.json",
      "version": "12"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.