cve/2019/CVE-2019-9792.md

### [CVE-2019-9792](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9792)
![](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%2060.6%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Version&message=%3C%2066%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=IonMonkey%20leaks%20JS_OPTIMIZED_OUT%20magic%20value%20to%20script&color=brighgreen)

### Description

The IonMonkey just-in-time (JIT) compiler can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

### POC

#### Reference
- http://packetstormsecurity.com/files/153106/Spidermonkey-IonMonkey-JS_OPTIMIZED_OUT-Value-Leak.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1532599

#### Github
- https://github.com/RUB-SysSec/JIT-Picker
- https://github.com/googleprojectzero/fuzzilli
- https://github.com/zhangjiahui-buaa/MasterThesis