CVEs-PoC/2021/CVE-2021-23351.md

### [CVE-2021-23351](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23351)
![](https://img.shields.io/static/v1?label=Product&message=github.com%2Fpires%2Fgo-proxyproto&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=unspecified%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Denial%20of%20Service%20(DoS)&color=brightgreen)

### Description

The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.

### POC

#### Reference
- https://github.com/pires/go-proxyproto/commit/7f48261db810703d173f27f3309a808cc2b49b8b

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