CVE-2012-1957

CVE-2012-1957 is a medium-severity vulnerability in Mozilla Firefox 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: 2% (79th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-79
• Affected product: Mozilla Firefox
• Published: 2012-07-18
• Last modified: 2026-06-16

Description

An unspecified parser-utility class in Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 does not properly handle EMBED elements within description elements in RSS feeds, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a feed.

Frequently asked questions

What is CVE-2012-1957?

An unspecified parser-utility class in Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 does not properly handle EMBED elements within description elements in RSS feeds, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a feed.

How severe is CVE-2012-1957?

CVE-2012-1957 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2012-1957 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-1957?

CVE-2012-1957 primarily affects Mozilla Firefox. In total, 127 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-1957?

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

When was CVE-2012-1957 published?

CVE-2012-1957 was published on 2012-07-18 and last updated on 2026-06-16.

References

• http://lists.opensuse.org/opensuse-security-announce/2012-07/msg00011.html
• http://lists.opensuse.org/opensuse-security-announce/2012-07/msg00012.html
• http://lists.opensuse.org/opensuse-security-announce/2012-07/msg00013.html
• http://lists.opensuse.org/opensuse-security-announce/2012-07/msg00016.html
• http://osvdb.org/84000
• http://rhn.redhat.com/errata/RHSA-2012-1088.html
• http://secunia.com/advisories/49965
• http://secunia.com/advisories/49968
• http://secunia.com/advisories/49972
• http://secunia.com/advisories/49977
• http://secunia.com/advisories/49979
• http://secunia.com/advisories/49992
• http://secunia.com/advisories/49993
• http://secunia.com/advisories/49994
• http://www.mozilla.org/security/announce/2012/mfsa2012-47.html
• http://www.securityfocus.com/bid/54583
• http://www.securitytracker.com/id?1027256
• http://www.securitytracker.com/id?1027257
• http://www.securitytracker.com/id?1027258
• http://www.ubuntu.com/usn/USN-1509-1
• http://www.ubuntu.com/usn/USN-1509-2
• http://www.ubuntu.com/usn/USN-1510-1
• https://bugzilla.mozilla.org/show_bug.cgi?id=750096
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16844

Affected products (127)

• cpe:2.3:a:mozilla:firefox:4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta10:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta11:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta12:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta5:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta6:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta7:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta8:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta9:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:5.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:7.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:8.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:8.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:9.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:9.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:11.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:12.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:12.0:beta6:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:13.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:thunderbird:5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:thunderbird:6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:thunderbird:6.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:thunderbird:6.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:thunderbird:7.0:*:*:*:*:*:*:*

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