CVE-2012-4203

CVE-2012-4203 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 6.8. 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-264.

Key facts

Description

The New Tab page in Mozilla Firefox before 17.0 uses a privileged context for execution of JavaScript code by bookmarklets, which allows user-assisted remote attackers to run arbitrary programs by leveraging a javascript: URL in a bookmark.

Frequently asked questions

What is CVE-2012-4203?
The New Tab page in Mozilla Firefox before 17.0 uses a privileged context for execution of JavaScript code by bookmarklets, which allows user-assisted remote attackers to run arbitrary programs by leveraging a javascript: URL in a bookmark.
How severe is CVE-2012-4203?
CVE-2012-4203 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2012-4203 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-4203?
CVE-2012-4203 primarily affects Mozilla Firefox. In total, 171 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-4203?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2012-4203 published?
CVE-2012-4203 was published on 2012-11-21 and last updated on 2026-06-16.

References

Affected products (171)

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