Is CVE-2019-9812 in the CISA KEV catalog?

No. CVE-2019-9812 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2019-9812?

CVE-2019-9812 has a CVSS v3 base score of 9.3 (CRITICAL).

What is the EPSS score for CVE-2019-9812?

CVE-2019-9812 has an EPSS score of 1.30% (67th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2019-9812?

Upgrade firefox on debian unstable to 69.0-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2019-9812

CRITICAL

9.3

CVSS v3

NVD

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.

How to fix

Remediation Available

firefoxDebian

Fixed in:69.0-1CVE-2019-9812

firefoxUbuntu

Fixed in:69.0+build2-0ubuntu0.16.04.4USN-4122-1

Fixed in:69.0+build2-0ubuntu0.18.04.1USN-4122-1

DeveloperEditionWindows application

Affected:60.9Fixed in:60.9Mozilla

Affected:61.0 68.1Fixed in:68.1Mozilla

Affected:69.0Fixed in:69.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:69.0Fixed in:69.0Mozilla

Affected:60.9Fixed in:60.9Mozilla

Affected:61.0 68.1Fixed in:68.1Mozilla

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeChanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H

Exploit Intelligence

1.30%probability of exploitation in 30 days

67thpercentile

Moderate risk: more likely to be exploited than 67% of all known CVEs.

References

Vendor Advisory3

Other references2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-25.