{"id":"CVE-2026-53181","state":"PUBLISHED","title":"vsock/vmci: fix sk_ack_backlog leak on failed handshake","description":"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.","publishedAt":"2026-06-25T08:38:55.994Z","updatedAt":"2026-10-15T01:22:34.587Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"22c587aa3ab1ab5264daff3ec32136fd30436c13","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"cf7090e255d74c4b61c51f8ede9fcacdd8393b5b","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"ea0b03d52881c12a8c634ea0d6cbfa61cefdb488","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"dfd853197615d322d3a88dbcab91fc0fd2096219","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"bcb275626055df7f8f947f1a349754b4004d9a15","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"ba9ad6015937a5e46ba1a31370e3efdec8abbdcc","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"9698582a4dd9c4a05889d7db96d4c0edc9e69cac","versionType":"git"},{"version":"d021c344051af91f42c5ba9fdedc176740cbd238","status":"affected","lessThan":"c05fa14db43ebef3bd862ca9d073981c0358b3f0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/vmci_transport.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.9","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/vmw_vsock/vmci_transport.c"]}],"references":["https://git.kernel.org/stable/c/22c587aa3ab1ab5264daff3ec32136fd30436c13","https://git.kernel.org/stable/c/cf7090e255d74c4b61c51f8ede9fcacdd8393b5b","https://git.kernel.org/stable/c/ea0b03d52881c12a8c634ea0d6cbfa61cefdb488","https://git.kernel.org/stable/c/dfd853197615d322d3a88dbcab91fc0fd2096219","https://git.kernel.org/stable/c/bcb275626055df7f8f947f1a349754b4004d9a15","https://git.kernel.org/stable/c/ba9ad6015937a5e46ba1a31370e3efdec8abbdcc","https://git.kernel.org/stable/c/9698582a4dd9c4a05889d7db96d4c0edc9e69cac","https://git.kernel.org/stable/c/c05fa14db43ebef3bd862ca9d073981c0358b3f0","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53181.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53181","state":"PUBLISHED","datePublished":"2026-06-25T08:38:55.994Z","dateUpdated":"2026-10-15T01:22:34.587Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.390Z"},"containers":{"cna":{"title":"vsock/vmci: fix sk_ack_backlog leak on failed handshake","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 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