What’s Vulnerable › Vulnerabilities

CVE-2019-8266

• Severity: critical (CVSS 9.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-03-08 · updated 2026-06-17
• Weakness: CWE-788

Description

UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnection::Copybuffer function in VNC client code, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. User interaction is required to trigger these vulnerabilities. These vulnerabilities have been fixed in revision 1208.

Affected products

• Kaspersky Lab UltraVNC: before 1.2.2.3 — fixed in 1.2.2.3

How to fix

Upgrade to a fixed version: Kaspersky Lab UltraVNC 1.2.2.3. Check the vendor advisory for mitigations.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf
• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-013-ultravnc-access-of-memory-location-after-end-of-buffer/
• https://www.us-cert.gov/ics/advisories/icsa-20-161-06
• https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf
• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-013-ultravnc-access-of-memory-location-after-end-of-buffer/
• https://www.us-cert.gov/ics/advisories/icsa-20-161-06

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