CVE-2019-9816 Explained : Impact and Mitigation

A vulnerability exists in manipulating JavaScript objects in object groups, potentially leading to type confusion and security check circumvention in Thunderbird, Firefox, and Firefox ESR.

Understanding CVE-2019-9816

This CVE involves a type confusion vulnerability in object groups and UnboxedObjects, affecting Mozilla Thunderbird, Firefox, and Firefox ESR.

What is CVE-2019-9816?

Type confusion may occur when manipulating JavaScript objects in object groups, allowing security check bypass within these groups.
The vulnerability is demonstrated with UnboxedObjects, not enabled by default in all supported releases.

The Impact of CVE-2019-9816

Thunderbird versions prior to 60.7, Firefox versions prior to 67, and Firefox ESR versions prior to 60.7 are susceptible to this vulnerability.

Technical Details of CVE-2019-9816

This section provides detailed technical information about the CVE.

Vulnerability Description

Vulnerability arises in the manipulation of JavaScript objects in object groups, leading to type confusion and potential security check circumvention.

Affected Systems and Versions

Affected products: Thunderbird, Firefox, Firefox ESR
Versions susceptible: Thunderbird < 60.7, Firefox < 67, Firefox ESR < 60.7

Exploitation Mechanism

Type confusion with object groups and UnboxedObjects

Mitigation and Prevention

Protect your systems from CVE-2019-9816 with the following steps:

Immediate Steps to Take

Update Thunderbird, Firefox, and Firefox ESR to versions 60.7 and 67 or higher, respectively.
Disable UnboxedObjects if not required for functionality.

Long-Term Security Practices

Regularly update software to the latest versions to patch vulnerabilities.
Implement secure coding practices to prevent type confusion and security check bypass.

Patching and Updates

Stay informed about security advisories from Mozilla and apply patches promptly.