CVEs-PoC/2021/CVE-2021-43539.md

### [CVE-2021-43539](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-43539)
![](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=%3C%2091.4.0%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Version&message=%3C%2095%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=GC%20rooting%20failure%20when%20calling%20wasm%20instance%20methods&color=brighgreen)

### Description

Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/ARPSyndicate/cvemon