CVE-2019-25600

UltraVNC Viewer 1.2.2.4 Denial of Service via Buffer Overflow

MEDIUM
6.5
CVSS Score
Published: March 22, 2026 at 01:38 PM UTC
Updated: June 17, 2026 at 02:32 AM UTC
1 product affected across 1 vendorUltraVNC

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-787

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