GHSA-5VRR-7H3C-F6HV

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

smb: client: require net admin for CIFS SWN netlink

CIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command. The intended sender is the cifs.witness helper, but the generic-netlink operation currently has no capability flag, so any local process can send RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness handler.

The same family exposes CIFS_GENL_MCGRP_SWN without multicast-group capability flags. Register messages sent to that group include the witness registration id and, for NTLM-authenticated mounts, the username, domain, and password attributes copied from the CIFS session. An unprivileged local process should not be able to join that group and receive those messages.

Require CAP_NET_ADMIN for incoming SWN_NOTIFY commands with GENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for joining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN. The cifs.witness service runs with the privileges needed for both operations.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64137"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:55Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: require net admin for CIFS SWN netlink\n\nCIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command.  The\nintended sender is the cifs.witness helper, but the generic-netlink\noperation currently has no capability flag, so any local process can send\nRESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness\nhandler.\n\nThe same family exposes CIFS_GENL_MCGRP_SWN without multicast-group\ncapability flags.  Register messages sent to that group include the witness\nregistration id and, for NTLM-authenticated mounts, the username, domain,\nand password attributes copied from the CIFS session.  An unprivileged\nlocal process should not be able to join that group and receive those\nmessages.\n\nRequire CAP_NET_ADMIN for incoming SWN_NOTIFY commands with\nGENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for\njoining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN.  The\ncifs.witness service runs with the privileges needed for both operations.",
  "id": "GHSA-5vrr-7h3c-f6hv",
  "modified": "2026-07-20T15:32:01Z",
  "published": "2026-07-19T18:31:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64137"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/969bc6370334a5b4720c5470783295d6484bbc95"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9919021a3b7974ae66a5f9915e3a48c10cfd409b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9cf7eb8919344932f909b2fac76296f7656fda8d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a3238b09c58f323e40743ce174cd0ab81b5c09ed"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a8d17d22db591099519a89f14dd24810daba74c3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c2397b93fbb6f44a788fff30f99be2c20cc5e50f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d1ebfce2c1d161186a82e77590bf7da2ea1bce91"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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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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