cve/2021/CVE-2021-22696.md

### [CVE-2021-22696](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22696)
![](https://img.shields.io/static/v1?label=Product&message=Apache%20CXF&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3C%203.4.3%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-400%20Uncontrolled%20Resource%20Consumption&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-918%20Server-Side%20Request%20Forgery%20(SSRF)&color=brighgreen)

### Description

CXF supports (via JwtRequestCodeFilter) passing OAuth 2 parameters via a JWT token as opposed to query parameters (see: The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request (JAR)). Instead of sending a JWT token as a "request" parameter, the spec also supports specifying a URI from which to retrieve a JWT token from via the "request_uri" parameter. CXF was not validating the "request_uri" parameter (apart from ensuring it uses "https) and was making a REST request to the parameter in the request to retrieve a token. This means that CXF was vulnerable to DDos attacks on the authorization server, as specified in section 10.4.1 of the spec. This issue affects Apache CXF versions prior to 3.4.3; Apache CXF versions prior to 3.3.10.

### POC

#### Reference
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpuoct2021.html

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