Vulnerability in Mozilla Firefox

CVE-2019-9812

Given a compromised sandboxed content process due to a separate vulnerability, it is possible to escape that sandbox by loading accounts.firefox.com in that process and forcing a log-in to a malicious Firefox Sync account. Preference settings that disable the sandbox are then synchronized to the local machine and the compromised browser would restart without the sandbox if a crash is triggered. This vulnerability affects Firefox ESR < 60.9, Firefox ESR < 68.1, and Firefox < 69.

EPSS: 0.013 (67.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H.

Affected products

References

Frequently asked questions

What is CVE-2019-9812?
CVE-2019-9812 is a critical-severity vulnerability in Mozilla Firefox. CVSS score: 9.3/10. Published 2020-01-08.
How severe is CVE-2019-9812?
Critical severity. CVSS v3 base score is 9.3 out of 10.