CVE-2025-64113: Emby Server Privilege Escalation Flaw

CVE-2025-64113 Overview

CVE-2025-64113 is a critical authentication bypass vulnerability affecting Emby Server, a popular user-installable home media server platform. This vulnerability allows an attacker to gain full administrative access to an Emby Server instance without requiring any authentication or specific preconditions beyond network access.

The flaw is classified under CWE-640 (Weak Password Recovery Mechanism for Forgotten Password), indicating issues within the password recovery or authentication handling mechanisms. Successful exploitation grants attackers complete control over Emby Server administration, enabling them to modify server configurations, access media libraries, create or delete user accounts, and potentially leverage the server for further malicious activities within the network.

Critical Impact

Unauthenticated attackers with network access can gain full administrative control of vulnerable Emby Server instances, compromising media server administration and potentially exposing sensitive user data.

Affected Products

• Emby Server versions below 4.9.1.81
• Emby Server version 4.9.2.6 (beta)

Discovery Timeline

• 2025-12-09 - CVE-2025-64113 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2025-64113

Vulnerability Analysis

This vulnerability stems from a weakness in the password recovery mechanism for forgotten passwords (CWE-640). The flaw allows unauthenticated attackers to bypass normal authentication controls and gain administrative privileges on the Emby Server platform.

The attack can be executed remotely over the network without requiring any user interaction or special privileges. The vulnerability affects the confidentiality, integrity, and availability of the target system at a high level, with additional limited impact on connected systems.

Emby Server installations that are exposed to untrusted networks, including internet-facing deployments, are at significant risk. No specific preconditions beyond basic network connectivity are required to exploit this vulnerability, making it particularly dangerous for publicly accessible instances.

Root Cause

The root cause of CVE-2025-64113 lies in a weak password recovery mechanism implementation. The authentication bypass occurs due to insufficient validation or flawed logic in the password reset functionality, allowing attackers to circumvent normal authentication requirements and directly access administrative functions.

Attack Vector

The attack vector is network-based, requiring only that an attacker can reach the vulnerable Emby Server instance. The exploitation flow involves:

1. An attacker identifies an exposed Emby Server running a vulnerable version (below 4.9.1.81)
2. The attacker exploits the weak password recovery mechanism to bypass authentication
3. Upon successful exploitation, the attacker gains full administrative access to the Emby Server administration interface
4. With administrative privileges, the attacker can modify configurations, access user data, and potentially compromise the broader network

The vulnerability mechanism involves exploiting weaknesses in the authentication flow. For detailed technical information, refer to the GitHub Security Advisory GHSA-95fv-5gfj-2r84.

Detection Methods for CVE-2025-64113

Indicators of Compromise

• Unexpected administrative account creations or modifications in Emby Server logs
• Unusual password reset requests or authentication bypass attempts in server logs
• Unauthorized changes to server configuration or media library settings
• Suspicious network connections to Emby Server ports from unknown IP addresses

Detection Strategies

• Monitor Emby Server logs for failed and successful authentication attempts, particularly those involving password recovery functions
• Implement network monitoring to detect unusual traffic patterns to Emby Server instances
• Use intrusion detection systems (IDS) to identify exploitation attempts targeting the authentication bypass
• Regularly audit administrative accounts and permissions for unauthorized changes

Monitoring Recommendations

• Enable verbose logging on Emby Server instances to capture detailed authentication events
• Configure alerts for new administrative user creation or privilege escalation events
• Monitor network traffic for reconnaissance activities targeting Emby Server ports
• Implement SIEM rules to correlate authentication anomalies across multiple server instances

How to Mitigate CVE-2025-64113

Immediate Actions Required

• Upgrade Emby Server to version 4.9.1.81 or later immediately
• Restrict network access to Emby Server instances using firewall rules
• Review and audit all administrative accounts for unauthorized access
• Enable additional authentication mechanisms such as reverse proxy authentication if available

Patch Information

Emby has addressed this vulnerability in version 4.9.1.81. Users should upgrade to this version or later to remediate the issue. The official security advisory is available at the Emby Security GitHub Advisory.

To update Emby Server:

1. Backup current server configuration and database
2. Download the latest stable release from the official Emby website
3. Follow the upgrade procedure for your operating system
4. Verify the installed version is 4.9.1.81 or higher after upgrade

Workarounds

• Place Emby Server behind a VPN or authenticated reverse proxy to limit network exposure
• Implement firewall rules to restrict access to trusted IP addresses only
• Disable public internet access to the Emby Server until patching is complete
• Monitor server logs closely for any suspicious authentication activity

# Example firewall rule to restrict Emby Server access (Linux iptables)
# Replace 192.168.1.0/24 with your trusted network range
# Replace 8096 with your Emby Server port if different

iptables -A INPUT -p tcp --dport 8096 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8096 -j DROP