Is CVE-2009-4129 being actively exploited?

CVE-2009-4129 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2009-4129?

CVE-2009-4129 has a CVSS 2.0 base score of 5.8 (MEDIUM).

CVE-2009-4129

MEDIUM · CVSS 5.8EPSS 0.8%EU EUVD

Race condition in Mozilla Firefox allows remote attackers to produce a JavaScript message with a spoofed domain association by writing the message in between the document request and document load for a web page in a different domain.

Key facts

CVSS score: 5.8 (v2.0)
Severity: MEDIUM
CVSS vector: AV:N/AC:M/Au:N/C:N/I:P/A:P
Weakness (CWE): CWE-362
EPSS score: 0.8% (55th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2009-4099)
Published: December 14, 2009
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2009-4099 in the EU Vulnerability Database. Last updated in EUVD on August 7, 2024.

View on the EU Vulnerability Database

Affected products

mozilla / firefox

References

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

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