CVE-2021-29490 : What You Need to Know

Jellyfin, a free software media system, versions prior to 10.7.3 are vulnerable to unauthenticated Server-Side Request Forgery (SSRF) attacks. This CVE allows attackers to perform unauthenticated GET requests through Remote Image endpoints.

Understanding CVE-2021-29490

This section discusses what CVE-2021-29490 is, its impact, technical details, and mitigation strategies.

What is CVE-2021-29490?

CVE-2021-29490 is a vulnerability found in Jellyfin versions <= 10.7.2 that allows unauthenticated SSRF attacks through the imageUrl parameter, potentially exposing internal and external HTTP servers.

The Impact of CVE-2021-29490

The vulnerability has a CVSS base score of 5.8 (Medium severity) and could lead to unauthorized access to HTTP servers visible from the Jellyfin server.

Technical Details of CVE-2021-29490

Let's dive deeper into the technical aspects of this vulnerability.

Vulnerability Description

CVE-2021-29490 in Jellyfin versions prior to 10.7.3 enables attackers to exploit SSRF by sending unauthenticated GET requests through specific image-related endpoints.

Affected Systems and Versions

Jellyfin versions <= 10.7.2 are affected by this vulnerability, exposing them to potential SSRF attacks.

Exploitation Mechanism

The vulnerability allows attackers to manipulate the imageUrl parameter to trigger unauthenticated requests to remote image endpoints.

Mitigation and Prevention

Here's how you can mitigate and prevent exploitation of CVE-2021-29490.

Immediate Steps to Take

To address the vulnerability, update Jellyfin to version 10.7.3 or later. As a temporary workaround, restrict external access to certain API endpoints or limit access to known-friendly IPs.

Long-Term Security Practices

Implement strict access controls, regular security updates, and continuous monitoring to prevent future SSRF attacks.

Patching and Updates

Regularly check for security patches and updates from Jellyfin to stay protected against known vulnerabilities.