GHSA-6GQ6-HXJH-9GRQ

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-25 09:31
VLAI
Details

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

vsock/vmci: fix sk_ack_backlog leak on failed handshake

When vmci_transport_recv_connecting_server() returns an error, vmci_transport_recv_listen() calls vsock_remove_pending() but never calls sk_acceptq_removed(). This leaves sk_ack_backlog incremented permanently.

Repeated handshake failures (malformed packets, queue pair alloc failure, event subscribe failure) cause sk_ack_backlog to climb toward sk_max_ack_backlog. Once it reaches the limit the listener permanently refuses all new connections with -ECONNREFUSED, a silent denial of service requiring a process restart to recover.

The two existing sk_acceptq_removed() calls in af_vsock.c do not cover this path: line 764 checks vsock_is_pending() which returns false after vsock_remove_pending(), and line 1889 is only reached on successful accept().

Fix by balancing sk_acceptq_added() with sk_acceptq_removed() on the error path.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53181"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:35Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/vmci: fix sk_ack_backlog leak on failed handshake\n\nWhen vmci_transport_recv_connecting_server() returns an error,\nvmci_transport_recv_listen() calls vsock_remove_pending() but never\ncalls sk_acceptq_removed(). This leaves sk_ack_backlog incremented\npermanently.\n\nRepeated handshake failures (malformed packets, queue pair alloc\nfailure, event subscribe failure) cause sk_ack_backlog to climb\ntoward sk_max_ack_backlog. Once it reaches the limit the listener\npermanently refuses all new connections with -ECONNREFUSED, a\nsilent denial of service requiring a process restart to recover.\n\nThe two existing sk_acceptq_removed() calls in af_vsock.c do not\ncover this path: line 764 checks vsock_is_pending() which returns\nfalse after vsock_remove_pending(), and line 1889 is only reached\non successful accept().\n\nFix by balancing sk_acceptq_added() with sk_acceptq_removed() on\nthe error path.",
  "id": "GHSA-6gq6-hxjh-9grq",
  "modified": "2026-06-25T09:31:20Z",
  "published": "2026-06-25T09:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53181"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22c587aa3ab1ab5264daff3ec32136fd30436c13"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9698582a4dd9c4a05889d7db96d4c0edc9e69cac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba9ad6015937a5e46ba1a31370e3efdec8abbdcc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bcb275626055df7f8f947f1a349754b4004d9a15"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c05fa14db43ebef3bd862ca9d073981c0358b3f0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf7090e255d74c4b61c51f8ede9fcacdd8393b5b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfd853197615d322d3a88dbcab91fc0fd2096219"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea0b03d52881c12a8c634ea0d6cbfa61cefdb488"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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