Vulnerability in Mozilla Firefox

CVE-2018-5116

WebExtensions with the "ActiveTab" permission are able to access frames hosted within the active tab even if the frames are cross-origin. Malicious extensions can inject frames from arbitrary origins into the loaded page and then interact with them, bypassing same-origin user expectations with this permission. This vulnerability affects Firefox < 58.

EPSS: 0.012 (64.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2018-5116?
CVE-2018-5116 is a critical-severity vulnerability in Mozilla Firefox, classified under Origin Validation Error. CVSS score: 9.8/10. Published 2018-06-11.
How severe is CVE-2018-5116?
Critical severity. CVSS v3 base score is 9.8 out of 10.