How severe is CVE-2012-1251?

CVE-2012-1251 has a CVSS 2.0 base score of 5.8, rated medium severity.

Is CVE-2012-1251 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-1251?

CVE-2012-1251 primarily affects Opera Opera Browser. In total, 114 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-1251?

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

When was CVE-2012-1251 published?

CVE-2012-1251 was published on 2012-06-04 and last updated on 2026-06-16.

CVE-2012-1251

CVE-2012-1251 is a medium-severity vulnerability in Opera Opera Browser with a CVSS 2.0 base score of 5.8. 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-310.

Key facts

Severity: Medium (CVSS 2.0 base score 5.8)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-310
Affected product: Opera Opera Browser
Published: 2012-06-04
Last modified: 2026-06-16

Description

Opera before 9.63 does not properly verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

Frequently asked questions

What is CVE-2012-1251?: Opera before 9.63 does not properly verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
How severe is CVE-2012-1251?: CVE-2012-1251 has a CVSS 2.0 base score of 5.8, rated medium severity.
Is CVE-2012-1251 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-1251?: CVE-2012-1251 primarily affects Opera Opera Browser. In total, 114 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-1251?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2012-1251 published?: CVE-2012-1251 was published on 2012-06-04 and last updated on 2026-06-16.

References

Affected products (114)

cpe:2.3:a:opera:opera_browser:*:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:1.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.10:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.10:beta1:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.10:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.10:beta3:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:2.12:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.00:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.10:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.21:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.50:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.51:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.60:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.61:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.62:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:3.62:beta:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:beta3:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:beta4:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:beta5:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.00:beta6:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.01:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:4.02:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta2:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta3:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta4:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta5:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta6:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta7:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.0:beta8:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.02:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.10:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.11:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:5.12:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:6.0:*:*:*:*:*:*:*
cpe:2.3:a:opera:opera_browser:6.0:beta1:*:*:*:*:*:*

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