What’s Vulnerable › Vulnerabilities

CVE-2019-8271

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 8.3% 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-122

Description

UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer handler, which can potentially result code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.

Affected products

• Siemens Sinumerik Access Mymachine/P2P: before 4.8 — fixed in 4.8
• Siemens Sinumerik Pcu Base Win10 Software/Ipc: before 14.00 — fixed in 14.00
• Siemens Sinumerik Pcu Base Win7 Software/Ipc: through 12.01
• Kaspersky Lab UltraVNC: before 1.2.2.3 — fixed in 1.2.2.3

How to fix

Upgrade to a fixed version: Siemens Sinumerik Access Mymachine/P2P 4.8; Siemens Sinumerik Pcu Base Win10 Software/Ipc 14.00; 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-19-018-ultravnc-heap-based-buffer-overflow/
• 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-19-018-ultravnc-heap-based-buffer-overflow/
• https://www.us-cert.gov/ics/advisories/icsa-20-161-06

Get alerted when CVE-2019-8271 or the next vulnerability affects your stack