cve/2021/CVE-2021-23999.md

### [CVE-2021-23999](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23999)
![](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%2078.10%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Version&message=%3C%2088%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Blob%20URLs%20may%20have%20been%20granted%20additional%20privileges&color=brighgreen)

### Description

If a Blob URL was loaded through some unusual user interaction, it could have been loaded by the System Principal and granted additional privileges that should not be granted to web content. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

### POC

#### Reference
- https://bugzilla.mozilla.org/show_bug.cgi?id=1691153

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