CVE-2019-17026 in Mozilla and Canonical Products
Published on March 2, 2020

Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.

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Known Exploited Vulnerability

This Mozilla Firefox IonMonkey JIT compiler Type Confusion Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.

The following remediation steps are recommended / required by May 3, 2022: Apply updates per vendor instructions.

Vulnerability Analysis

CVE-2019-17026 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. It has an exploitability score of 2.8 out of four. The potential impact of an exploit of this vulnerability is considered to be very high.

What is an Object Type Confusion Vulnerability?

The program allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

CVE-2019-17026 has been classified to as an Object Type Confusion vulnerability or weakness.

Products Associated with CVE-2019-17026

You can be notified by stack.watch whenever vulnerabilities like CVE-2019-17026 are published in these products:

Mozilla Firefox

Mozilla FireFox Extended Support Release (ESR)

Mozilla Thunderbird

Canonical Ubuntu Linux

What versions are vulnerable to CVE-2019-17026?

Mozilla Firefox Fixed in Version 72.0.1
Mozilla Thunderbird Fixed in Version 68.4.1
Mozilla Firefox Fixed in Version 68.4.1