SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-12398

By using the reflected URL in some special resource URIs, such as chrome:, it is possible to inject stylesheets and bypass Content Security Policy (CSP).

MEDIUM 6.5EPSS 1.62%

Does this matter?

Lower severity and a low EPSS score (1.62%). Track it; it rarely justifies an emergency change on its own.

Description

By using the reflected URL in some special resource URIs, such as chrome:, it is possible to inject stylesheets and bypass Content Security Policy (CSP). This vulnerability affects Firefox < 63.

CVSS 3.0
6.5 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS
1.62% probability · 76th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Affected
mozilla/firefox · canonical/ubuntu linux
Source
security@mozilla.org
EPSS trend
0%3%5%27 October 2026: 1.62%27 October 202627 October 2026

EPSS 1.6% since 27 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.