High [CVE-2026-53181] fix sk_ack_backlog leak on failed handshake
This high-severity Red Hat Linux advisory covers CVE-2026-53181 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
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.
Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: kernel-rt.
Is CVE-2026-53181 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53181 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-53181?
The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 15 days ago·verify at source
Get an email when Red Hat Linux Kernel publishes the next one.
See Red Hat Linux Kernel's last 90 days of advisories first. Then choose one product with live alerts free for life, or a free month of real-time alerts on everything with the severity, the fixed version and the vendor's link (card needed, then US$15/month; we email you before the first charge).
More Red Hat Linux advisories
- CVE-2026-111497Oct 22, 2026Out-of-Bounds Write in Google Brotli Decoder
- CVE-2026-109619Oct 21, 2026fatal error handling retains stale request state leading to use-after-free
- CVE-2026-109618Oct 21, 2026OOM bailout during request parsing leads to memory corruption and RCE
- CVE-2026-119977Oct 31, 2026Arbitrary code execution via predictable upgrade staging paths
- CVE-2026-97229Oct 13, 2026integer overflow issue in CI/CD regular expression compiler
- CVE-2026-64849Aug 17, 2026Unauthenticated full-read SSRF in webhook delivery: _validate_webhook_url bypassed
iPhone and Android apps · New on the App Store
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.