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TI-2019-15653 Aliases CVE-2019-25600GHSA-6w7v-w6gw-pm7w

UltraVNC Viewer 1.2.2.4 Denial of Service via Buffer Overflow

Priority HIGH 70CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

UltraVNC Viewer 1.2.2.4 contains a denial of service vulnerability that allows attackers to crash the application by supplying an oversized string to the VNC Server input field. Attackers can paste a malicious string containing 256 repeated characters into the VNC Server field and click Connect to trigger a buffer overflow that crashes the viewer.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00701 53rd 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

VendorProductAffected versionsFixed inStatusSource
uvncUltraVNC Viewer1.2.2.4—No fix listedCNA
  • UltraVNC Viewer Vendoruvnc Affected 1.2.2.4 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2019-25600
  2. 2026-10-03 Alias added: GHSA-6w7v-w6gw-pm7w

References

Exploit 1

Other 2

  • TI-2020-19268 UltraVNC Launcher 1.2.4.0 - 'RepeaterHost' Denial of Service CVSS 4.0MEDIUM 6.7
  • TI-2026-04323 UltraVNC Service version.dll uncontrolled search path CVSS 4.0HIGH 7.3
  • TI-2019-15654 UltraVNC Launcher 1.2.2.4 Denial of Service Buffer Overflow CVSS 4.0MEDIUM 6.9
  • TI-2019-15616 PCHelpWareV2 1.0.0.5 Denial of Service via SC Creation CVSS 4.0MEDIUM 6.9
  • TI-2020-19267 UltraVNC Launcher 1.2.4.0 - 'Password' Denial of Service CVSS 4.0MEDIUM 6.7
  • TI-2019-15617 PCHelpWareV2 1.0.0.5 Denial of Service via Group Field CVSS 4.0MEDIUM 6.8
See all 40 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences