cve/2019/CVE-2019-9900.md

### [CVE-2019-9900](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9900)
![](https://img.shields.io/static/v1?label=Product&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brighgreen)

### Description

When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.

### POC

#### Reference
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h
- https://hackerone.com/reports/536954

#### Github
- https://github.com/ARPSyndicate/cvemon
- https://github.com/alphaSeclab/sec-daily-2019
- https://github.com/solo-io/envoy-cves