The SOCKS4 Proxy in Microsoft Internet Security and Acceleration (ISA) Server 2004 SP1 and SP2 allows remote attackers to obtain potentially sensitive information (the destination IP address of another user's session) via an empty packet.
Conclusion & alert: CVE-2007-4991 is rated Moderate Risk (48.8/100): CVSS Medium severity, with high exploitation likelihood (EPSS 16.15%, 97th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. 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 | 47.85% | 16.15% | -31.70% |
| 2 | 2026-05-10 | 47.46% | 47.85% | +0.40% |
| 3 | 2025-03-30 | — | 47.46% | — |
Full EPSS history (14 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| microsoft | isa_server | 2004 | cpe:2.3:a:microsoft:isa_server:2004:sp1:*:*:*:*:*:* |
| microsoft | isa_server | 2004 | cpe:2.3:a:microsoft:isa_server:2004:sp2:*:*:*:*:*:* |