Cerulean Studios Trillian 3.1 Basic does not check SSL certificates during MSN authentication, which allows remote attackers to obtain MSN credentials via a man-in-the-middle attack with a spoofed SSL certificate.
Conclusion & alert: CVE-2009-4831 is rated Moderate Risk (48.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.38%). 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 | 0.45% | 1.38% | +0.93% |
| 2 | 2025-03-30 | 0.50% | 0.45% | -0.05% |
| 3 | 2025-03-29 | — | 0.50% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.8 | 2.0 | MEDIUM |
|
8.6 | 4.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| cerulean_studios | trillian | 3.1 | cpe:2.3:a:cerulean_studios:trillian:3.1:*:*:*:basic:*:*:* |
| URL | Tags |
|---|---|
| http://secunia.com/advisories/35620 | Broken Link |
| http://www.securityfocus.com/archive/1/504573/100/0/threaded | Broken Link Third Party Advisory VDB Entry |
| http://www.securityfocus.com/bid/35509 | Broken Link Third Party Advisory VDB Entry |
| https://exchange.xforce.ibmcloud.com/vulnerabilities/51400 | Third Party Advisory VDB Entry |