Medium severity · published Jun 25, 2026
CVE-2026-53181
vsock/vmci: fix sk_ack_backlog leak on failed handshake
5.5
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 2% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
3.9 before 5.10.259; 5.11 before 5.15.210; 5.16 before 6.1.176; 6.2 before 6.6.143; 6.7 before 6.12.94; 6.13 before 6.18.36; +7 more · source: NVD
LI
Linux · Linux
d021c344051af91f42c5ba9fdedc176740cbd238 before 22c587aa3ab1ab5264daff3ec32136fd30436c13; d021c344051af91f42c5ba9fdedc176740cbd238 before cf7090e255d74c4b61c51f8ede9fcacdd8393b5b; d021c344051af91f42c5ba9fdedc176740cbd238 before ea0b03d52881c12a8c634ea0d6cbfa61cefdb488; d021c344051af91f42c5ba9fdedc176740cbd238 before dfd853197615d322d3a88dbcab91fc0fd2096219; d021c344051af91f42c5ba9fdedc176740cbd238 before bcb275626055df7f8f947f1a349754b4004d9a15; d021c344051af91f42c5ba9fdedc176740cbd238 before ba9ad6015937a5e46ba1a31370e3efdec8abbdcc; +3 more · source: vendor