Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-79680
StatePUBLISHED
AssignerQt
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-24 11:16:47 UTC
Updated2026-09-24 21:08:22 UTC
DescriptionAuthentication 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.

Risk And Classification

Primary CVSS: v4.0 4.5 MEDIUM from a59d8014-47c4-4630-ab43-e1b13cbe58e3

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:D/RE:L/U:X

Problem Types: CWE-288 | CWE-288 CWE-288 Authentication Bypass Using an Alternate Path or Channel

VersionSourceTypeScoreSeverityVector
4.0a59d8014-47c4-4630-ab43-e1b13cbe58e3Secondary4.5MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/C...
4.0CNACVSS4.5MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/V...

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:D/RE:L/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Qt Qt affected 6.4.0 6.8.9 python Not specified
CNA Qt Qt affected 6.9.0 6.11.3 python Not specified

References

ReferenceSourceLinkTags
codereview.qt-project.org/c/qt/tqtc-qtvncserver/+/759160 a59d8014-47c4-4630-ab43-e1b13cbe58e3 codereview.qt-project.org
wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products a59d8014-47c4-4630-ab43-e1b13cbe58e3 wiki.qt.io
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