IRONSMITHINTEL
CRITICALCVSS10.0
|
Actively Exploited
|CISA KEV|CVE-2019-11708|Auth: none — unauthenticated|Reboot: required|Manual only

Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability

Mozilla Firefox and Thunderbird contain a sandbox escape vulnerability that could result in remote code execution.

Published Jul 23, 2019 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-06-13 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Improper Input Validation (CWE-20) vulnerability in Mozilla Firefox and Thunderbird. Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

📧

Phishing link

🖼

Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running firefox: v < 60.7.2, v < 67.0.4; thunderbird: v < 60.7.2
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2022-05-23 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2022-06-13.

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply updates per vendor instructions.

References

    1
    Vendor advisory: https://bugzilla.mozilla.org/show_bug.cgi?id=1559858
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2019-11708
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-11708
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