CVE-2019-9812 — Mozilla: Sandbox escape through Firefox Sync

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CRITICAL

Mozilla: Sandbox escape through Firefox Sync

Published Jan 8, 2020

9.3

CRITICAL

CVSS 3.1

EPSS 1.51%

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

Vendor Mozilla Product Firefox Default
n/a
- Version
  before 69
  Status
  affected
  Constraints
  -
Vendor Mozilla Product Firefox ESR Default
n/a
- Version
  before 60.9
  Status
  affected
  Constraints
  -
- Version
  before 68.1
  Status
  affected
  Constraints
  -

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

Mozilla

Firefox

n/a

Version	Status	Constraints
before 69	affected	-

Mozilla

Firefox ESR

n/a

Version	Status	Constraints
before 60.9	affected	-
before 68.1	affected	-

Red Hat Enterprise Linux 6

firefox-0:60.9.0-1.el6_10

Fixed · RHSA-2019:2694
Red Hat Enterprise Linux 7

firefox-0:60.9.0-1.el7_7

Fixed · RHSA-2019:2729
Red Hat Enterprise Linux 8

firefox-0:68.1.0-1.el8_0

Fixed · RHSA-2019:2663
Red Hat Enterprise Linux 5

firefox

Out of support scope

Product	Package	State	Advisory
Red Hat Enterprise Linux 6	firefox-0:60.9.0-1.el6_10	Fixed	RHSA-2019:2694
Red Hat Enterprise Linux 7	firefox-0:60.9.0-1.el7_7	Fixed	RHSA-2019:2729
Red Hat Enterprise Linux 8	firefox-0:68.1.0-1.el8_0	Fixed	RHSA-2019:2663
Red Hat Enterprise Linux 5	firefox	Out of support scope	n/a

Remediation

No remediation recorded yet.

Metrics

1.51% 0.01510

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.

EPSS probability 0.01510

Score over time

2021–2026

EPSS v1
EPSS v5
EPSS v2
EPSS v3
EPSS v4

Percentile over time

EPSS v1
EPSS v5
EPSS v2
EPSS v3
EPSS v4

Table of values (16 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 2, 2026	1.51% (0.01510)	73.53th	v5 (v2026.06.15)
Jun 15, 2026	1.30% (0.01302)	66.63th	v5 (v2026.06.15)
May 30, 2026	0.28% (0.00281)	51.64th	v4 (v2025.03.14)
Jul 20, 2024	0.53% (0.00526)	77.19th	v3 (v2023.03.01)
Mar 8, 2024	0.53% (0.00526)	76.44th	v3 (v2023.03.01)
Jan 15, 2024	0.53% (0.00526)	74.44th	v3 (v2023.03.01)
Nov 12, 2023	0.37% (0.00371)	69.54th	v3 (v2023.03.01)
Oct 28, 2023	0.27% (0.00269)	64.15th	v3 (v2023.03.01)
Mar 7, 2023	0.22% (0.00225)	58.91th	v3 (v2023.03.01)
Mar 6, 2023	1.02% (0.01018)	40.69th	v2 (v2022.01.01)
Apr 1, 2022	1.02% (0.01018)	36.86th	v2 (v2022.01.01)
Feb 4, 2022	4.13% (0.04134)	68.25th	v2 (v2022.01.01)
Feb 3, 2022	5.68% (0.05680)	80.53th	v1
Jan 6, 2022	5.68% (0.05680)	80.34th	v1
Jan 5, 2022	1.32% (0.01324)	70.80th	v5 (v2026.06.15)
Apr 14, 2021	1.32% (0.01324)	0.00th	v1

Weaknesses (1)

CWE-250

Execution with Unnecessary Privileges

References (10)

https://access.redhat.com/security/cve/CVE-2019-9812
Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1538008
x_refsource_CONFIRMPermissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1538015
x_refsource_MISCPermissions Required
https://bugzilla.redhat.com/show_bug.cgi?id=1748660
Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2019-9812
https://www.cve.org/CVERecord?id=CVE-2019-9812
https://www.mozilla.org/en-US/security/advisories/mfsa2019-27/#CVE-2019-9812
https://www.mozilla.org/security/advisories/mfsa2019-25/
x_refsource_CONFIRMVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-26/
x_refsource_CONFIRMVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-27/
x_refsource_CONFIRMVendor Advisory

Link	Providers	Tags
https://access.redhat.com/security/cve/CVE-2019-9812		Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1538008		x_refsource_CONFIRMPermissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1538015		x_refsource_MISCPermissions Required
https://bugzilla.redhat.com/show_bug.cgi?id=1748660		Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2019-9812
https://www.cve.org/CVERecord?id=CVE-2019-9812
https://www.mozilla.org/en-US/security/advisories/mfsa2019-27/#CVE-2019-9812
https://www.mozilla.org/security/advisories/mfsa2019-25/		x_refsource_CONFIRMVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-26/		x_refsource_CONFIRMVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-27/		x_refsource_CONFIRMVendor Advisory