CVEs-PoC/2021/CVE-2021-44686.md

### [CVE-2021-44686](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44686)
![](https://img.shields.io/static/v1?label=Product&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brightgreen)

### Description

calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in html_preprocess_rules in ebooks/conversion/preprocess.py.

### POC

#### Reference
- https://bugs.launchpad.net/calibre/+bug/1951979
- https://github.com/dwisiswant0/advisory/issues/18

#### Github
- https://github.com/ARPSyndicate/cvemon
- https://github.com/engn33r/awesome-redos-security