The Windows Messenger ActiveX control in msgsc.dll in Microsoft Windows XP SP2 and SP3 allows remote attackers to execute arbitrary code via unspecified vectors that "corrupt the system state," aka "Microsoft Windows Messenger ActiveX Control Vulnerability."
Conclusion & alert: CVE-2011-1243 is rated High Risk (74.6/100): CVSS Critical severity, with high exploitation likelihood (EPSS 43.73%, 97th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +3.26% 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 | 2026-02-15 | 40.47% | 43.73% | +3.26% |
| 2 | 2026-01-20 | 40.89% | 40.47% | -0.42% |
| 3 | 2025-12-28 | — | 40.89% | — |
Full EPSS history (24 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.3 | 2.0 | HIGH |
|
8.6 | 10.0 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| microsoft | windows_xp | — | cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:* |
| microsoft | windows_xp | — | cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:* |