GHSA-RFJW-G695-7WXH

Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-31 15:30
VLAI
Details

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

Drivers: hv: Don't reset VMBus connection state on error/exit paths

In two places, current code forces vmbus_connection.conn_state to DISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect() calls vmbus_initiate_unload(), which unloads the VMBus connection only if the conn_state is CONNECTED. Consequently, the connection remains and the Hyper-V host might continue to send messages or post VMBus interrupts.

The problem was introduced in commit 74347a99e73ae ("x86/Hyper-V: Unload vmbus channel in hv panic callback"), in that vmbus_initiate_unload() started checking the current connection state before doing the unload. This commit removed some occurrences where conn_state was forced to DISCONNECTED, but these two remained, apparently due to an oversight at the time.

Fix this by not forcing conn_state to DISCONNECTED during VMBus exit, or if a failure occurs when establishing the connection in the first place. Whatever value conn_state has at the time is then read by vmbus_initiate_unload() to determine if there is a connection to be unloaded.

Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-99216"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T11:17:43Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nDrivers: hv: Don\u0027t reset VMBus connection state on error/exit paths\n\nIn two places, current code forces vmbus_connection.conn_state to\nDISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect()\ncalls vmbus_initiate_unload(), which unloads the VMBus connection\nonly if the conn_state is CONNECTED. Consequently, the connection\nremains and the Hyper-V host might continue to send messages or post\nVMBus interrupts.\n\nThe problem was introduced in commit 74347a99e73ae (\"x86/Hyper-V:\nUnload vmbus channel in hv panic callback\"), in that\nvmbus_initiate_unload() started checking the current connection\nstate before doing the unload. This commit removed some occurrences\nwhere conn_state was forced to DISCONNECTED, but these two remained,\napparently due to an oversight at the time.\n\nFix this by not forcing conn_state to DISCONNECTED during VMBus exit,\nor if a failure occurs when establishing the connection in the first\nplace. Whatever value conn_state has at the time is then read by\nvmbus_initiate_unload() to determine if there is a connection to\nbe unloaded.",
  "id": "GHSA-rfjw-g695-7wxh",
  "modified": "2026-10-31T15:30:23Z",
  "published": "2026-10-28T12:31:08Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99216"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2732210132f92aca0622b5134027990a809279d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2939215d57bc8e4189290544fca78f3809ac3ef8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2e5ffbf1e41abbf6e02ce28115107938f55ff646"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3195546a377c2d8d176d837e8baad5ce15d11195"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/deef3ab5129ae4c45662c957cdab3739eb047fb1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ec31dc39e835ccde0930daccece8c492d28282fc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f47ce27af80b87cc684d5c12b65506af498ac7e5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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