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How the mentioned CVE works: In Gitea before version 1.20.1, a cross-site scripting vulnerability exists due to inadequate validation of URL schemes in user-supplied links. The application fails to block forbidden schemes such as “javascript:” when processing links. This allows attackers to craft malicious links that, when clicked by victims, execute arbitrary JavaScript code in the context of the victim’s browser. The vulnerability arises from missing input sanitization and output encoding in link handling functions. Attackers can embed these malicious links in various parts of the application, like issues, comments, or user profiles, where they are stored and displayed to other users. When a user interacts with the link, the JavaScript payload runs, potentially leading to session hijacking, account takeover, or data theft. This is a stored XSS attack requiring user interaction, but social engineering can increase exploitation likelihood. The flaw stems from the absence of a whitelist for safe URL schemes, permitting dangerous ones that trigger code execution. Fixes in version 1.20.1 involve implementing strict scheme validation and proper encoding to neutralize such threats.
Platform: Gitea
Version: before 1.20.1
Vulnerability: Cross-site Scripting
Severity: Moderate
Date: 2025-12-26
Prediction: Patch in 1.20.1
What Undercode Say:
Analytics:
gitea --version curl -s http://localhost:3000/api/v1/version | grep -o '1.20.[0-9]'
<a href="javascript:alert('XSS')">Click me</a>
How Exploit:
Create links with javascript: URLs in user-input fields like issues or comments. When victims click, scripts execute to steal cookies or perform actions.
Protection from this CVE:
Upgrade to Gitea 1.20.1. Validate URL schemes to allow only http, https, ftp. Implement Content Security Policy.
Impact:
Account compromise, data theft, unauthorized system actions via session hijacking or redirection.
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Sources:
Reported By: github.com
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