CVE-2019-9812Public exploitNetwork attack vector

Sandbox escape via attacker-controlled synced preferences

Published Jan 8, 2020 · Updated Aug 4, 2024

Sandbox escape in Firefox before 69 and Firefox ESR before 60.9 or 68.1 allows attackers to disable content-process isolation. Firefox Sync accepted attacker-created services.sync.prefs.sync.* control preferences, then applied synchronized sandbox and process-model settings locally. Exploitation requires a separate content-process compromise, forced sign-in to an attacker-controlled Sync account, and a triggered crash.

CVSS severity9.3
Critical
EPSS probability1.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in Firefox before 69 and Firefox ESR before 60.9 or 68.1 allows attackers to disable content-process isolation. Firefox Sync accepted attacker-created services.sync.prefs.sync.* control preferences, then applied synchronized sandbox and process-model settings locally. Exploitation requires a separate content-process compromise, forced sign-in to an attacker-controlled Sync account, and a triggered crash.

The record

CVE
CVE-2019-9812
Published
Jan 8, 2020
Updated
Aug 4, 2024
Vendor
Mozilla
Product
Firefox
Classifications
T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=before 69

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=before 69
Mozilla · Firefox ESRversion=before 60.9; version=before 68.1

Published CVSS scores

9.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H
5.8NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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