cve/2021/CVE-2021-23986.md

### [CVE-2021-23986](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23986)
![](https://img.shields.io/static/v1?label=Product&message=Firefox&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%2087%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=A%20malicious%20extension%20could%20have%20performed%20credential-less%20same%20origin%20policy%20violations&color=brighgreen)

### Description

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.

### POC

#### Reference
- https://bugzilla.mozilla.org/show_bug.cgi?id=1692623

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