UltraVNC revision 1211 has a heap buffer overflow vulnerability in VNC server code inside file transfer offer handler, which can potentially in result code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1212.
Conclusion & alert: CVE-2019-8274 is rated High Risk (76.4/100): CVSS Critical severity, with high exploitation likelihood (EPSS 8.26%, 94th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +4.26% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 4.00% | 8.26% | +4.26% |
| 2 | 2026-02-07 | 4.51% | 4.00% | -0.51% |
| 3 | 2025-12-23 | — | 4.51% | — |
Full EPSS history (18 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| uvnc | ultravnc | < 1.2.2.3 | cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:* |
| siemens | sinumerik_access_mymachine\/p2p | < 4.8 | cpe:2.3:a:siemens:sinumerik_access_mymachine\/p2p:*:*:*:*:*:*:*:* |
| siemens | sinumerik_pcu_base_win10_software\/ipc | < 14.00 | cpe:2.3:a:siemens:sinumerik_pcu_base_win10_software\/ipc:*:*:*:*:*:*:*:* |
| siemens | sinumerik_pcu_base_win7_software\/ipc | <= 12.01 | cpe:2.3:a:siemens:sinumerik_pcu_base_win7_software\/ipc:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf | Third Party Advisory |
| https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-021-ultravnc-heap-based-buffer-overflow/ | Third Party Advisory |
| https://www.us-cert.gov/ics/advisories/icsa-20-161-06 | Third Party Advisory US Government Resource |