CVE-2023-3354Network attack vector

Remote denial of service via VNC handshake cleanup

Published Jul 11, 2023 · Updated Feb 13, 2025

QEMU built-in VNC server before 8.1.0 allows remote attackers to cause a denial of service through a failed TLS handshake. When connection limits trigger cleanup, a failed handshake connection is cleaned up twice, dereferencing a NULL pointer. No authentication is required, and the consequence is service interruption rather than data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

QEMU built-in VNC server before 8.1.0 allows remote attackers to cause a denial of service through a failed TLS handshake. When connection limits trigger cleanup, a failed handshake connection is cleaned up twice, dereferencing a NULL pointer. No authentication is required, and the consequence is service interruption rather than data disclosure or modification.

The record

CVE
CVE-2023-3354
Published
Jul 11, 2023
Updated
Feb 13, 2025
Vendor
Red Hat
Product
Red Hat OpenStack Platform
Classifications
CWE-476, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat OpenStack PlatformAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Fedora Project · Fedora LinuxAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8 Advanced VirtualizationAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
QEMU Project · QEMUAffected versions are unavailable in this record.

Published CVSS scores

7.5Red Hat, Inc.CVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1498Network Denial of Service

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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