An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0. The value of the X-Forwarded-Host header overwrites the value of the Host header in proxied requests. The value of X-Forwarded-Host header is not checked against the whitelist of hosts that ZCS is allowed to proxy to (the zimbraProxyAllowedDomains setting).
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Collaboration | Zimbra | 8.8.15 (including) | 8.8.15 (including) |
| Collaboration | Zimbra | 9.0.0 (including) | 9.0.0 (including) |