UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that allows attackers to crash the application by manipulating VNC Server input. Attackers can generate a malformed 256-byte payload and paste it into the VNC Server connection dialog to trigger an application crash.
CVSS v4.0 Metrics
Exploitability
Attack VectorLocal
ComplexityLow
RequirementsNone
PrivilegesNone
User InteractionActive
Threat
Exploit MaturityUnreported
Vulnerable System
ConfidentialityNone
IntegrityNone
AvailabilityLow
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | cve.org | initial, patch: Unavailable | 1.0 |
Affected Software
| Vendor | Product | Version |
|---|
| UltraVNC Team | UltraVNC Viewer | 1.2.4.0 |
Published: 2026-02-05
