CVE-2012-4210

CVE-2012-4210 is a critical-severity vulnerability in Mozilla Firefox 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-264.

Key facts

• Severity: Critical (CVSS 2.0 base score 9.3)
• EPSS exploit prediction: 4% (88th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-264
• Affected product: Mozilla Firefox
• Published: 2012-11-21
• Last modified: 2026-06-16

Description

The Style Inspector in Mozilla Firefox before 17.0 and Firefox ESR 10.x before 10.0.11 does not properly restrict the context of HTML markup and Cascading Style Sheets (CSS) token sequences, which allows user-assisted remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted stylesheet.

Frequently asked questions

What is CVE-2012-4210?

The Style Inspector in Mozilla Firefox before 17.0 and Firefox ESR 10.x before 10.0.11 does not properly restrict the context of HTML markup and Cascading Style Sheets (CSS) token sequences, which allows user-assisted remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted stylesheet.

How severe is CVE-2012-4210?

CVE-2012-4210 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2012-4210 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-4210?

CVE-2012-4210 primarily affects Mozilla Firefox. In total, 179 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-4210?

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-2012-4210 published?

CVE-2012-4210 was published on 2012-11-21 and last updated on 2026-06-16.

References

• http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00021.html
• http://lists.opensuse.org/opensuse-security-announce/2013-01/msg00022.html
• http://lists.opensuse.org/opensuse-updates/2012-11/msg00090.html
• http://lists.opensuse.org/opensuse-updates/2012-11/msg00093.html
• http://rhn.redhat.com/errata/RHSA-2012-1482.html
• http://secunia.com/advisories/51359
• http://secunia.com/advisories/51369
• http://secunia.com/advisories/51434
• http://secunia.com/advisories/51439
• http://www.mandriva.com/security/advisories?name=MDVSA-2012:173
• http://www.mozilla.org/security/announce/2012/mfsa2012-104.html
• http://www.palemoon.org/releasenotes-ng.shtml
• http://www.securityfocus.com/bid/56646
• http://www.ubuntu.com/usn/USN-1638-1
• http://www.ubuntu.com/usn/USN-1638-2
• http://www.ubuntu.com/usn/USN-1638-3
• https://bugzilla.mozilla.org/show_bug.cgi?id=796866
• https://exchange.xforce.ibmcloud.com/vulnerabilities/80182
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16833

Affected products (179)

• cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.7:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.7.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.8:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9:rc:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.10:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.10.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0:preview_release:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.7:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.8:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:beta1:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:beta2:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.7:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.8:*:*:*:*:*:*:*

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