CVE-2019-9792: Critical severity Mozilla Firefox vulnerability

Published Mar 19, 2019
·
Updated

Last updated 25 August 2025

Other sources

The IonMonkey just-in-time (JIT) compiler can leak an internal JSOPTIMIZEDOUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash.

External Reference:

https://www.mozilla.org/en-US/security/advisories/mfsa2019-08/#CVE-2019-9792

— Red Hat

The IonMonkey just-in-time (JIT) compiler can leak an internal JSOPTIMIZEDOUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash.

Affected Software

18 affected componentsFixes available
Mozilla Firefox<66
66
Mozilla Thunderbird<60.6
60.6
Mozilla Firefox<66.0
Mozilla Firefox ESR<60.6.0
Mozilla Thunderbird<60.6.0
redhat Enterprise Linux=8.0
redhat Enterprise Linux Eus=8.1
redhat Enterprise Linux Eus=8.2
redhat Enterprise Linux Eus=8.4
redhat Enterprise Linux Server Aus=8.2
redhat Enterprise Linux Server Aus=8.4
redhat Enterprise Linux Server Tus=8.2
redhat Enterprise Linux Server Tus=8.4
Mozilla Firefox ESR<60.6
60.6
Mozilla Firefox<60.6.0
debian/firefox
152.0-1
debian/firefox-esr
115.14.0esr-1~deb11u1140.11.0esr-1~deb11u1140.10.2esr-1~deb12u1140.12.0esr-1~deb12u1140.10.2esr-1~deb13u1140.12.0esr-1~deb13u1140.11.0esr-1140.12.0esr-1
debian/thunderbird
1:115.12.0-1~deb11u11:140.12.0esr-1~deb11u11:140.10.1esr-1~deb12u11:140.11.0esr-1~deb12u11:140.10.1esr-1~deb13u11:140.11.0esr-1~deb13u11:140.11.0esr-11:140.12.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 66
  2. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 60.6
  3. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 60.6
  4. Upgrade

    Upgrade debian/firefox to a version that resolves this vulnerability.

    Fixed in 152.0-1
  5. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 115.14.0esr-1~deb11u1Fixed in 140.11.0esr-1~deb11u1Fixed in 140.10.2esr-1~deb12u1Fixed in 140.12.0esr-1~deb12u1Fixed in 140.10.2esr-1~deb13u1Fixed in 140.12.0esr-1~deb13u1Fixed in 140.11.0esr-1Fixed in 140.12.0esr-1
  6. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.12.0esr-1~deb11u1Fixed in 1:140.10.1esr-1~deb12u1Fixed in 1:140.11.0esr-1~deb12u1Fixed in 1:140.10.1esr-1~deb13u1Fixed in 1:140.11.0esr-1~deb13u1Fixed in 1:140.11.0esr-1Fixed in 1:140.12.0esr-1
  7. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 115.14.0esr-1~deb11u1
  8. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.11.0esr-1~deb11u1
  9. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.10.2esr-1~deb12u1
  10. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.12.0esr-1~deb12u1
  11. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.10.2esr-1~deb13u1
  12. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.12.0esr-1~deb13u1
  13. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.11.0esr-1
  14. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.12.0esr-1
  15. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:115.12.0-1~deb11u1
  16. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1~deb11u1
  17. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.10.1esr-1~deb12u1
  18. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1~deb12u1
  19. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.10.1esr-1~deb13u1
  20. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1~deb13u1
  21. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1
  22. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1

Event History

Mar 19, 2019
CVE Published
12:00 AM
Mar 20, 2019
Data Sourced
via Red Hat·02:14 AM
DescriptionSeverityAffected Software
Apr 26, 2019
CVE Published
via MITRE·04:13 PM
Data Sourced
via MITRE·04:13 PM
DescriptionWeakness
Data Sourced
via NVD·05:29 PM
DescriptionSeverityWeaknessAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·11:33 PM
Description
Feb 19, 2026
Data Sourced
via Ubuntu·06:00 PM
RemedyDescriptionSeverityAffected Software
Jun 18, 2026
Data Sourced
via Debian·04:04 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is CVE-2019-9792?

CVE-2019-9792 is a vulnerability in the IonMonkey just-in-time (JIT) compiler that can lead to memory corruption and potentially exploitable crashes.

2

Which software is affected by CVE-2019-9792?

CVE-2019-9792 affects Thunderbird and Firefox versions 66.0 and above.

3

What is the severity of CVE-2019-9792?

CVE-2019-9792 has a severity rating of critical (9/10).

4

How can CVE-2019-9792 be fixed?

To fix CVE-2019-9792, update your Thunderbird or Firefox to version 66.0 or above.

5

Where can I find more information about CVE-2019-9792?

You can find more information about CVE-2019-9792 on the Mozilla website and Bugzilla.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203