CVE-2019-25601Public exploit

Application crash via oversized viewer path

Published Mar 22, 2026 · Updated Mar 22, 2026

Out-of-bounds write in UltraVNC Launcher 1.2.2.4 allows local users to crash the application through its Properties dialog. The Path vncviewer.exe property accepts a 300-byte string without enforcing the destination buffer's bounds, and processing that value terminates the launcher. Exploitation requires local interactive access to enter the crafted value and click OK; the demonstrated consequence is an application crash only.

CVSS severity6.9
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in UltraVNC Launcher 1.2.2.4 allows local users to crash the application through its Properties dialog. The Path vncviewer.exe property accepts a 300-byte string without enforcing the destination buffer's bounds, and processing that value terminates the launcher. Exploitation requires local interactive access to enter the crafted value and click OK; the demonstrated consequence is an application crash only.

The record

CVE
CVE-2019-25601
Published
Mar 22, 2026
Updated
Mar 22, 2026
Vendor
UltraVNC Team
Product
UltraVNC Launcher
Classifications
CWE-787, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.2.2.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

UltraVNC Team · UltraVNC Launcherversion=1.2.2.4

Published CVSS scores

6.2VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.9VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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