CVE-2026-53181

Listener denial of service via backlog leak

Published Jun 25, 2026 · Updated Jun 25, 2026

Denial of service in the Linux kernel vsock/VMCI transport allows local users to make a listener refuse all new connections. On a failed handshake, vmci_transport_recv_listen() removes the pending socket without decrementing sk_ack_backlog, so repeated failures exhaust sk_max_ack_backlog. Access that can send malformed VMCI handshake packets is required; once saturated, the listener returns ECONNREFUSED until its process restarts.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel vsock/VMCI transport allows local users to make a listener refuse all new connections. On a failed handshake, vmci_transport_recv_listen() removes the pending socket without decrementing sk_ack_backlog, so repeated failures exhaust sk_max_ack_backlog. Access that can send malformed VMCI handshake packets is required; once saturated, the listener returns ECONNREFUSED until its process restarts.

The record

CVE
CVE-2026-53181
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.9
  2. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <22c587aa3ab1ab5264daff3ec32136fd30436c13
  3. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <9698582a4dd9c4a05889d7db96d4c0edc9e69cac
  4. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <ba9ad6015937a5e46ba1a31370e3efdec8abbdcc
  5. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <bcb275626055df7f8f947f1a349754b4004d9a15
  6. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <c05fa14db43ebef3bd862ca9d073981c0358b3f0
  7. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <cf7090e255d74c4b61c51f8ede9fcacdd8393b5b
  8. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <dfd853197615d322d3a88dbcab91fc0fd2096219
  9. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <ea0b03d52881c12a8c634ea0d6cbfa61cefdb488

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.9; version=d021c344051af91f42c5ba9fdedc176740cbd238 <22c587aa3ab1ab5264daff3ec32136fd30436c13; version=d021c344051af91f42c5ba9fdedc176740cbd238 <9698582a4dd9c4a05889d7db96d4c0edc9e69cac; version=d021c344051af91f42c5ba9fdedc176740cbd238 <ba9ad6015937a5e46ba1a31370e3efdec8abbdcc; version=d021c344051af91f42c5ba9fdedc176740cbd238 <bcb275626055df7f8f947f1a349754b4004d9a15; version=d021c344051af91f42c5ba9fdedc176740cbd238 <c05fa14db43ebef3bd862ca9d073981c0358b3f0; version=d021c344051af91f42c5ba9fdedc176740cbd238 <cf7090e255d74c4b61c51f8ede9fcacdd8393b5b; version=d021c344051af91f42c5ba9fdedc176740cbd238 <dfd853197615d322d3a88dbcab91fc0fd2096219; version=d021c344051af91f42c5ba9fdedc176740cbd238 <ea0b03d52881c12a8c634ea0d6cbfa61cefdb488

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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