The Web Navigator in Siemens WinCC before 7.2 Update 1, as used in SIMATIC PCS7 8.0 SP1 and earlier and other products, exhibits different behavior for NetBIOS user names depending on whether the user account exists, which allows remote authenticated users to enumerate account names via crafted URL parameters.
Conclusion & alert: CVE-2013-3959 is rated Moderate Risk (40.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.33%). Core evidence: EPSS rose +1.17% over the last day, indicating growing attacker interest. Mandatory action: Review affected assets and schedule 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 | 0.16% | 1.33% | +1.17% |
| 2 | 2025-04-27 | 0.26% | 0.16% | -0.10% |
| 3 | 2025-03-17 | — | 0.26% | — |
Full EPSS history (5 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 4.0 | 2.0 | MEDIUM |
|
8.0 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| siemens | simatic_pcs7 | <= 8.0 | cpe:2.3:a:siemens:simatic_pcs7:*:sp1:*:*:*:*:*:* |
| siemens | simatic_pcs7 | 8.0 | cpe:2.3:a:siemens:simatic_pcs7:8.0:*:*:*:*:*:*:* |
| siemens | wincc | <= 7.2 | cpe:2.3:a:siemens:wincc:*:*:*:*:*:*:*:* |
| siemens | wincc | 7.0 | cpe:2.3:a:siemens:wincc:7.0:*:*:*:*:*:*:* |
| siemens | wincc | 7.0 | cpe:2.3:a:siemens:wincc:7.0:sp1:*:*:*:*:*:* |
| siemens | wincc | 7.0 | cpe:2.3:a:siemens:wincc:7.0:sp2:*:*:*:*:*:* |
| siemens | wincc | 7.0 | cpe:2.3:a:siemens:wincc:7.0:sp3:*:*:*:*:*:* |
| siemens | wincc | 7.1 | cpe:2.3:a:siemens:wincc:7.1:*:*:*:*:*:*:* |
| siemens | wincc | 7.1 | cpe:2.3:a:siemens:wincc:7.1:sp1:*:*:*:*:*:* |