CVE-2026-79680

Medium

Description

Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module. An attacker using a specially modified VNC client that violates the RFB protocol can bypass Qt VNC Server's password authentication and gain unauthorized remote access to the shared application, compromising the confidentiality and integrity of the session.

SeverityMedium

CVSS4.5

Exploit probability—

ProductQt

PublishedSep 24, 2026

First seenSep 24, 2026

Weakness typeCWE-288CWE-288

How to fix

Update

qt qt6.8.9, 6.11.3 or later

Patches

codereview.qt-project.org/c/qt/tqtc-qtvncserver/+/759160

Affected products

Product	Affected versions	Fixed in
qt qt	6.4.0 ≤ v < 6.8.9, 6.9.0 ≤ v < 6.11.3	6.8.9, 6.11.3

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