Overview
The vulnerability, identified as CVE-2025-53528, affects Cadwyn, a community-driven modern Stripe-like API versioning system created in FastAPI. This vulnerability is particularly concerning as it could lead to a system compromise or data leakage, posing a significant risk to any organization that utilizes Cadwyn in their applications.
Vulnerability Summary
CVE ID: CVE-2025-53528
Severity: High (CVSS: 7.6)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
Cadwyn | Versions before 5.4.3
How the Exploit Works
The vulnerability lies in the “/docs” endpoint of the Cadwyn application. The version parameter of this endpoint is not correctly sanitized, leading to a Reflected XSS attack vulnerability. This flaw allows an attacker to inject malicious JavaScript code. When a user clicks a manipulated link (a one-click attack), the code is executed within the user’s session. This could allow an attacker to hijack the user’s session, potentially leading to system compromise or data leakage.
Conceptual Example Code
An attacker could exploit this vulnerability by sending a specially crafted HTTP request, such as:
GET /docs?version=<script>malicious_script_here</script> HTTP/1.1
Host: vulnerable-host.example.comIn this example, “malicious_script_here” would be replaced with the actual malicious JavaScript code.
Mitigation Guidance
Users are strongly advised to apply the vendor patch by updating Cadwyn to version 5.4.3 or later. As a temporary mitigation, users can implement a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to monitor and block suspicious activities.
