Multiple buffer overflows in the (a) Session Clustering Daemon and the (b) mod_cluster module in the Zend Platform 2.2.1 and earlier allow remote attackers to cause a denial of service (crash) or execute arbitrary code via a (1) empty or (2) crafted PHP session identifier (PHPSESSID).
Conclusion & alert: CVE-2006-4431 is rated Moderate Risk (61.3/100): CVSS High severity, with high exploitation likelihood (EPSS 4.38%, 90th 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 | 4.56% | 4.38% | -0.17% |
| 2 | 2025-04-17 | 4.38% | 4.56% | +0.17% |
| 3 | 2025-03-30 | — | 4.38% | — |
Full EPSS history (9 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| zend | zend_platform | <= 2.2.1a | cpe:2.3:a:zend:zend_platform:*:a:*:*:*:*:*:* |