cve/2021/CVE-2021-21002.md

### [CVE-2021-21002](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21002)
![](https://img.shields.io/static/v1?label=Product&message=FL%20COMSERVER&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=UNI%20232%2F422%2F485%20(2313452)%3C%202.40%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-772%20Missing%20Release%20of%20Resource%20after%20Effective%20Lifetime&color=brighgreen)

### Description

In Phoenix Contact FL COMSERVER UNI in versions < 2.40 a invalid Modbus exception response can lead to a temporary denial of service.

### POC

#### Reference
- https://cert.vde.com/en-us/advisories/vde-2021-022

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