UltraVNC Viewer 1.2.4.0 - 'VNCServer' Denial of Service
Priority MEDIUM 60CWE-770Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-770.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00404 34th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| UltraVNC Team | UltraVNC Viewer | 1.2.4.0 | — | No fix listed | CNA |
- UltraVNC Viewer VendorUltraVNC Team Affected 1.2.4.0 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2020-37134
- 2026-10-03 Alias added: GHSA-w28g-7hwj-hqwj
References
Exploit 1
Other 1
Sources
- CVE-2020-37134 · CVE Program
- CVE-2020-37134 · NVD
- FIRST EPSS
- GHSA-w28g-7hwj-hqwj · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences