How severe is CVE-2012-4142?

CVE-2012-4142 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2012-4142 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-4142?

CVE-2012-4142 primarily affects Opera Opera Browser. In total, 43 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-4142?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2012-4142 published?

CVE-2012-4142 was published on 2012-08-06 and last updated on 2026-06-16.

CVE-2012-4142

CVE-2012-4142 is a medium-severity vulnerability in Opera Opera Browser with a CVSS 2.0 base score of 4.3. 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-79.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Opera Opera Browser
Published: 2012-08-06
Last modified: 2026-06-16

Description

Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, ignores some characters in HTML documents in unspecified circumstances, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via a crafted document.

Frequently asked questions

What is CVE-2012-4142?: Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, ignores some characters in HTML documents in unspecified circumstances, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via a crafted document.
How severe is CVE-2012-4142?: CVE-2012-4142 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2012-4142 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-4142?: CVE-2012-4142 primarily affects Opera Opera Browser. In total, 43 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-4142?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2012-4142 published?: CVE-2012-4142 was published on 2012-08-06 and last updated on 2026-06-16.

References

Affected products (43)

cpe:2.3:a:opera:opera_browser:*:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:12.00:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.00:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.00:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.00:beta3:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.01:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.10:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.10:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.11:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.50:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.50:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.50:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.51:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.52:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.52:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.52:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.53:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.53:b:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.53:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.54:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.60:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.60:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.61:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.62:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:10.63:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.00:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.01:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.10:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.10:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.11:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.50:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.50:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.51:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.52:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.52.1100:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.60:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.60:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:11.61:*:*:*:*:*:*:*

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