Gitea 1.22.0 - Stored XSS

# Exploit Title: Stored XSS in Gitea
# Date: 27/08/2024
# Exploit Authors: Catalin Iovita & Alexandru Postolache
# Vendor Homepage: (https://github.com/go-gitea/gitea)
# Version: 1.22.0
# Tested on: Linux 5.15.0-107, Go 1.23.0
# CVE: CVE-2024-6886

## Vulnerability Description
Gitea 1.22.0 is vulnerable to a Stored Cross-Site Scripting (XSS) vulnerability. This vulnerability allows an attacker to inject malicious scripts that get stored on the server and executed in the context of another user's session.

## Steps to Reproduce
1. Log in to the application.
2. Create a new repository or modify an existing repository by clicking the Settings button from the `$username/$repo_name/settings` endpoint.
3. In the Description field, input the following payload:

    <a href=javascript:alert()>XSS test</a>

4. Save the changes.
5. Upon clicking the repository description, the payload was successfully injected in the Description field. By clicking on the message, an alert box will appear, indicating the execution of the injected script.