CVE-2009-4100

CVE-2009-4100 is a critical-severity vulnerability in Yoono with a CVSS 2.0 base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Description

Yoono extension before 6.1.1 for Firefox performs certain operations with chrome privileges, which allows user-assisted remote attackers to execute arbitrary commands and perform cross-domain scripting attacks via DOM event handlers such as onload.

Frequently asked questions

What is CVE-2009-4100?
Yoono extension before 6.1.1 for Firefox performs certain operations with chrome privileges, which allows user-assisted remote attackers to execute arbitrary commands and perform cross-domain scripting attacks via DOM event handlers such as onload.
How severe is CVE-2009-4100?
CVE-2009-4100 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2009-4100 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-4100?
CVE-2009-4100 primarily affects Yoono. In total, 33 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-4100?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2009-4100 published?
CVE-2009-4100 was published on 2009-11-29 and last updated on 2026-06-16.

References

Affected products (33)

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