### [CVE-2020-26959](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26959)
![](https://img.shields.io/static/v1?label=Product&message=Firefox%20ESR&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=Firefox&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=Thunderbird&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Use-after-free%20in%20WebRequestService&color=brighgreen)

### Description

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

### POC

#### Reference
- https://bugzilla.mozilla.org/show_bug.cgi?id=1669466
- https://bugzilla.mozilla.org/show_bug.cgi?id=1669466

#### Github
No PoCs found on GitHub currently.