CVE-2020-26948
📋 TL;DR
This CVE describes a Server-Side Request Forgery (SSRF) vulnerability in Emby Server that allows attackers to make unauthorized requests from the server to internal or external systems. Attackers can exploit the ImageURL parameter in the Items/RemoteSearch/Image endpoint to access internal network resources or services. All Emby Server instances before version 4.5.0 are affected.
💻 Affected Systems
- Emby Server
📦 What is this software?
Emby by Emby
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access sensitive internal services, exfiltrate data, or pivot to other systems on the network, potentially leading to full network compromise.
Likely Case
Attackers scan internal networks, access metadata services (like AWS IMDS), or interact with internal APIs to gather information or perform limited actions.
If Mitigated
With proper network segmentation and firewall rules, impact is limited to the Emby server itself or specific allowed network segments.
🎯 Exploit Status
Public exploit scripts exist and demonstrate simple HTTP requests to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.5.0 and later
Vendor Advisory: https://emby.media/community/index.php?/topic/92130-emby-server-450-release/
Restart Required: Yes
Instructions:
1. Download Emby Server 4.5.0 or later from official sources. 2. Stop the Emby Server service. 3. Install the updated version. 4. Restart the Emby Server service.
🔧 Temporary Workarounds
Network Access Control
allRestrict network access to the Emby Server instance using firewalls or network segmentation.
Reverse Proxy Filtering
allConfigure reverse proxy (like nginx or Apache) to block or sanitize requests to the vulnerable endpoint.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Emby Server from sensitive internal resources
- Deploy web application firewall (WAF) rules to block SSRF patterns targeting the ImageURL parameter
🔍 How to Verify
Check if Vulnerable:
Check if Emby Server version is below 4.5.0 via web interface Dashboard or server logs.Check Version:
Check web interface at http://[emby-server]:8096/web/dashboard.html or examine server startup logs.Verify Fix Applied:
Confirm version is 4.5.0 or higher and test the /Items/RemoteSearch/Image endpoint with controlled SSRF payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to /Items/RemoteSearch/Image with external or internal IPs in ImageURL parameter
- Outbound connections from Emby Server to unexpected internal services
Network Indicators:
- Emby Server making requests to internal metadata services (169.254.169.254, 192.168.x.x ranges)
- Unexpected outbound traffic patterns from Emby Server
SIEM Query:
source="emby.log" AND (uri_path="/Items/RemoteSearch/Image" AND (ImageURL CONTAINS "http://" OR ImageURL CONTAINS "https://"))