CVE-2023-3354

Improper i/o watch removal in tls handshake can lead to remote unauthenticated denial of service

HIGH
7.5
CVSS Score
Published: July 11, 2023 at 04:16 PM UTC
Updated: June 17, 2026 at 06:13 AM UTC
5 products affected across 3 vendorsFedoraEnterprise LinuxQEMU

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Severity
HIGH7.5
Exploit prediction
EPSS 2%

Description

A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 8.1.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 6 (unaffected)
Vendor states this is fixed in 7 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

7.5HIGHredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-476

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