{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64137",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64137"
  ],
  "published": "2026-07-19T15:41:06Z",
  "summary": "smb: client: require net admin for CIFS SWN netlink",
  "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.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.176",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64137"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9cf7eb8919344932f909b2fac76296f7656fda8d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9919021a3b7974ae66a5f9915e3a48c10cfd409b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/969bc6370334a5b4720c5470783295d6484bbc95"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a3238b09c58f323e40743ce174cd0ab81b5c09ed"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a8d17d22db591099519a89f14dd24810daba74c3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c2397b93fbb6f44a788fff30f99be2c20cc5e50f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d1ebfce2c1d161186a82e77590bf7da2ea1bce91"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - Exploitation requires local access via generic-netlink syscalls (socket/bind/sendmsg/setsockopt on NETLINK_GENERIC), not remote SMB or network packet handling.\nAC:L - An unprivileged attacker can reliably join the SWN multicast group and send crafted SWN_NOTIFY commands; registration IDs are exposed in multicast register messages, with no races or uncontrollable conditions.\nPR:L - Before the fix, no capability checks guarded SWN_NOTIFY or multicast group membership, so any unprivileged local user could exploit without CAP_NET_ADMIN or user-namespace tricks.\nUI:N - Exploitation is passive (multicast subscription) or active (netlink injection) and does not require any victim action at attack time beyond pre-existing witness-enabled CIFS mounts.\nS:U - Impact is confined to the local kernel/CIFS client security domain (credential theft and connection manipulation); it does not cross VM, container, or IOMMU boundaries.\nC:H - Multicast register messages disclose NTLM username, domain, and plaintext password from active CIFS witness sessions to any local subscriber.\nI:H - Forged CLIENT_MOVE notifications redirect SMB reconnects to attacker-controlled endpoints, compromising connection integrity and enabling MITM against mounted cluster shares.\nA:H - Forged RESOURCE_CHANGE notifications force CIFS reconnect cycles on all channels, enabling reliable denial-of-service against witness-enabled mounts."
    }
  }
}