### [CVE-2019-11759](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11759)
![](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=Stack%20buffer%20overflow%20in%20HKDF%20output&color=brighgreen)

### Description

An attacker could have caused 4 bytes of HMAC output to be written past the end of a buffer stored on the stack. This could be used by an attacker to execute arbitrary code or more likely lead to a crash. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

### POC

#### Reference
- https://bugzilla.mozilla.org/show_bug.cgi?id=1577953
- https://bugzilla.mozilla.org/show_bug.cgi?id=1577953

#### Github
- https://github.com/MrE-Fog/cryptofuzz
- https://github.com/guidovranken/cryptofuzz