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CVE-2026-53181

Full vulnerability record from the local CVENow database.

Description

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.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-25 09:16:35.470000
Last modified
2026-11-06 17:18:12.733000
View original CVE JSON 
{
  "id": "CVE-2026-53181",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-25T09:16:35.470",
  "lastModified": "2026-11-06T17:18:12.733",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
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