No exploitation reportedFix available

CVE-2019-9812

Q: Is CVE-2019-9812 actively exploited?

Active exploitation of CVE-2019-9812 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2019-9812?

CVE-2019-9812 has a CVSS v3 base score of 9.3 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H.

No exploitation reported by the sources we read.

Published2020-01-08
Fixed in69.0 · 68.1 · 60.9

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2020-01-0822:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-9812?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-9812?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Mozilla firefox

Branch	Affected	Fixed in	Source
69.0	< 69.0	69.0	NVD
68.1	≥ 61.0, < 68.1	68.1	NVD
60.9	< 60.9	60.9	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Mozilla firefox to 69.0 · 68.1 · 60.9

Advisories and patches

www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.3read 2026-10-23
NVDCVSS 2.05.8read 2026-10-23
FIRST EPSSEPSS score1.5 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H
Published: 2020-01-08
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2019-9812?

Is CVE-2019-9812 actively exploited?

Active exploitation of CVE-2019-9812 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

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

CVE-2019-9812 has a CVSS v3 base score of 9.3 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H.

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