What’s Vulnerable › Vulnerabilities

CVE-2019-9812

• Severity: critical (CVSS 9.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-01-08 · updated 2026-06-17

Description

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.

Affected products

• Mozilla Firefox: before 60.9; before 69.0; from 61.0 before 68.1 — fixed in 60.9, 68.1, 69.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 60.9, 68.1, 69.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1538008
• https://bugzilla.mozilla.org/show_bug.cgi?id=1538015
• https://www.mozilla.org/security/advisories/mfsa2019-25/
• https://www.mozilla.org/security/advisories/mfsa2019-26/
• https://www.mozilla.org/security/advisories/mfsa2019-27/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1538008
• https://bugzilla.mozilla.org/show_bug.cgi?id=1538015
• https://www.mozilla.org/security/advisories/mfsa2019-25/
• https://www.mozilla.org/security/advisories/mfsa2019-26/
• https://www.mozilla.org/security/advisories/mfsa2019-27/

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