CVE-2019-25600
CVE-2019-25600 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: Medium (CVSS 3.x base score 6.5)
- CVSS v4: 7.1
- EPSS exploit prediction: 1% (48th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2019-19942
- Weakness: CWE-787
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2019-25600?
- 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.
- How severe is CVE-2019-25600?
- CVE-2019-25600 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2019-25600 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2019-25600?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2019-25600 have an EU (EUVD) identifier?
- Yes. CVE-2019-25600 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2019-19942.
- When was CVE-2019-25600 published?
- CVE-2019-25600 was published on 2026-03-22 and last updated on 2026-06-17.
References
- https://www.exploit-db.com/exploits/46702
- https://www.uvnc.com/
- https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html
- https://www.vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow
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