2021-29982 | Mozilla Firefox/Thunderbird JIT Optimizer information disclosure

By Max On Aug 20, 2021

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4.1	$0-$5k	0.52

A vulnerability, which was classified as problematic, has been found in Mozilla Firefox and Thunderbird up to 90.x (Web Browser). This issue affects an unknown function of the component JIT Optimizer. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. Impacted is confidentiality. The summary by CVE is:

Due to incorrect JIT optimization, we incorrectly interpreted data from the wrong type of object, resulting in the potential leak of a single bit of memory. This vulnerability affects Firefox < 91 and Thunderbird < 91.

The weakness was published 08/18/2021. It is possible to read the advisory at mozilla.org. The identification of this vulnerability is CVE-2021-29982 since 04/01/2021. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/19/2021).

Upgrading to version 91.0 eliminates this vulnerability. The upgrade is hosted for download at mozilla.org.

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