Is CVE-2009-4171 being actively exploited?

CVE-2009-4171 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2009-4171?

CVE-2009-4171 has a CVSS 2.0 base score of 4.3 (MEDIUM).

CVE-2009-4171

MEDIUM · CVSS 4.3EPSS 5.1%EU EUVD

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.

Key facts

CVSS score: 4.3 (v2.0)
Severity: MEDIUM
CVSS vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness (CWE): CWE-119
EPSS score: 5.1% (92th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2009-4141)
Published: December 2, 2009
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2009-4141 in the EU Vulnerability Database. Last updated in EUVD on August 7, 2024.

View on the EU Vulnerability Database

Affected products

yahoo / messenger

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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