Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module (CVE-2026-79680) | HOL Guard CVE

Medium · CVSS 4.5CVE-2026-79680

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

Answer in brief

CVE-2026-79680 records a Medium severity (CVSS 4.5) vulnerability in Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module. The current sources do not mark it as known exploited. The current feed maps qt/qt (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 24, 2026First seen by HOL Sep 24, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 4.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps qt/qt (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
qt/qtgeneric	>=6.4.0 <6.8.9 \|\| >=6.9.0 <6.11.3	6.8.9, 6.11.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for qt/qt.
Review the reported fix. Update qt/qt to 6.8.9 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 24, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.