Answer in brief
CVE-2026-53181 records a Medium severity (CVSS 5.5) vulnerability in vsock/vmci: fix sk_ack_backlog leak on failed handshake. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=d021c344051af91f42c5ba9fdedc176740cbd238 <22c587aa3ab1ab5264daff3ec32136fd30436c13 || >=d021c344051af91f42c5ba9fdedc176740cbd238 <cf7090e255d74c4b61c51f8ede9fcacdd8393b5b || >=d021c344051af91f42c5ba9fdedc176740cbd238 <ea0b03d52881c12a8c634ea0d6cbfa61cefdb488 || >=d021c344051af91f42c5ba9fdedc176740cbd238 <dfd853197615d322d3a88dbcab91fc0fd2096219 || >=d021c344051af91f42c5ba9fdedc176740cbd238 <bcb275626055df7f8f947f1a349754b4004d9a15 || >=d021c344051af91f42c5ba9fdedc176740cbd238 <ba9ad6015937a5e46ba1a31370e3efdec8abbdcc || >=d021c344051af91f42c5ba9fdedc176740cbd238 <9698582a4dd9c4a05889d7db96d4c0edc9e69cac || >=d021c344051af91f42c5ba9fdedc176740cbd238 <c05fa14db43ebef3bd862ca9d073981c0358b3f0 | 22c587aa3ab1ab5264daff3ec32136fd30436c13, cf7090e255d74c4b61c51f8ede9fcacdd8393b5b, ea0b03d52881c12a8c634ea0d6cbfa61cefdb488, dfd853197615d322d3a88dbcab91fc0fd2096219, bcb275626055df7f8f947f1a349754b4004d9a15, ba9ad6015937a5e46ba1a31370e3efdec8abbdcc, 9698582a4dd9c4a05889d7db96d4c0edc9e69cac, c05fa14db43ebef3bd862ca9d073981c0358b3f0 |
| Linux/Linuxgeneric | 3.9 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
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.
Quoted source text, attributed separately from HOL analysis.