SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2012-1961

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 do not properly handle duplicate values in X-Frame-Options headers, which makes it easier for…

MEDIUM 4.3EPSS 2.12%

Does this matter?

Lower severity and a low EPSS score (2.12%). Track it; it rarely justifies an emergency change on its own.

Description

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 do not properly handle duplicate values in X-Frame-Options headers, which makes it easier for remote attackers to conduct clickjacking attacks via a FRAME element referencing a web site that produces these duplicate values.

CVSS 2.0
4.3 MEDIUMAV:N/AC:M/Au:N/C:N/I:P/A:N
EPSS
2.12% probability · 82th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20
Affected
mozilla/firefox · mozilla/thunderbird · mozilla/thunderbird esr · mozilla/seamonkey
Source
cve@mitre.org
EPSS trend
0%3%5%26 October 2026: 2.12%26 October 202626 October 2026

EPSS 2.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.