An ActiveX control in YahooBridgeLib.dll for Yahoo! Messenger 9.0.0.2162, and possibly other 9.0 versions, allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) by calling the RegisterMe method with a long argument.
Conclusion & alert: CVE-2009-4171 is rated High Exploit Risk (66.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.09%, 91th percentile). Core evidence: 3 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.94% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| 10092 | exploit_db | edb | 2009-11-12 | Exploit-DB ↗ |
| 33350 | exploit_db | edb | 2009-11-12 | Exploit-DB ↗ |
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
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 | 3.15% | 5.09% | +1.94% |
| 2 | 2025-03-30 | 3.40% | 3.15% | -0.25% |
| 3 | 2025-03-29 | — | 3.40% | — |
Full EPSS history (7 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 4.3 | 2.0 | MEDIUM |
|
8.6 | 2.9 | [email protected] |