CVE-2019-11691: Use After Free

Published May 21, 2019
·
Updated

A use-after-free vulnerability can occur when working with XMLHttpRequest (XHR) in an event loop, causing the XHR main thread to be called after it has been freed. This results in a potentially exploitable crash.

External Reference:

https://www.mozilla.org/en-US/security/advisories/mfsa2019-14/#CVE-2019-11691

Other sources

A use-after-free vulnerability can occur when working with XMLHttpRequest (XHR) in an event loop, causing the XHR main thread to be called after it has been freed. This results in a potentially exploitable crash.

Mozilla

Affected Software

9 affected componentsFixes available
Mozilla Thunderbird<60.7
60.7
Mozilla Firefox<67.0
Mozilla Firefox ESR<60.7
Mozilla Thunderbird<60.7
Mozilla Firefox<67
67
Mozilla Firefox ESR<60.7
60.7
debian/firefox
138.0-1
debian/firefox-esr
115.14.0esr-1~deb11u1128.9.0esr-1~deb11u1128.8.0esr-1~deb12u1128.10.0esr-1~deb12u1128.9.0esr-2128.10.0esr-1
debian/thunderbird
1:115.12.0-1~deb11u11:128.10.0esr-1~deb11u11:128.8.0esr-1~deb12u11:128.10.0esr-1~deb12u11:128.9.0esr-11:128.10.0esr-1

Event History

May 21, 2019
CVE Published
via Mozilla·12:00 AM
May 22, 2019
Data Sourced
via Red Hat·01:41 AM
DescriptionSeverityAffected Software
Jul 23, 2019
CVE Published
via MITRE·01:23 PM
Data Sourced
via MITRE·01:23 PM
DescriptionWeakness
Jan 11, 2024
Data Sourced
via Launchpad·11:14 PM
Description
Sep 16, 2024
Data Sourced
via Ubuntu·02:09 AM
RemedyDescriptionSeverityAffected Software
Apr 20, 2025
Data Sourced
via Debian·04:06 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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-2019-11691?

CVE-2019-11691 is a use-after-free vulnerability that can occur when working with XMLHttpRequest (XHR) in an event loop, causing a potentially exploitable crash in Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

2

How does CVE-2019-11691 affect Mozilla Firefox?

CVE-2019-11691 affects Mozilla Firefox versions up to exclusive 67.

3

How does CVE-2019-11691 affect Mozilla Firefox ESR?

CVE-2019-11691 affects Mozilla Firefox ESR versions up to exclusive 60.7.

4

How does CVE-2019-11691 affect Thunderbird?

CVE-2019-11691 affects Thunderbird versions up to exclusive 60.7.

5

What is the severity of CVE-2019-11691?

The severity of CVE-2019-11691 is critical, with a CVSS score of 9.8.

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