CVE-2025-10127: Daikin Security Gateway Auth Bypass Flaw

CVE-2025-10127 Overview

CVE-2025-10127 is an authorization bypass vulnerability affecting the Daikin Europe N.V. Security Gateway. The vulnerability stems from a user-controlled key weakness that allows attackers to bypass authentication mechanisms entirely. An unauthorized attacker could gain access to the system without requiring prior credentials, potentially compromising the integrity and availability of connected industrial control systems.

Critical Impact
Unauthorized attackers can bypass authentication and gain full access to the Daikin Security Gateway without credentials, potentially affecting connected HVAC and building automation systems.

Affected Products

Daikin Europe N.V. Security Gateway

Discovery Timeline

September 11, 2025 - CVE-2025-10127 published to NVD
September 18, 2025 - Last updated in NVD database

Technical Details for CVE-2025-10127

Vulnerability Analysis

This authorization bypass vulnerability (CWE-640: Weak Password Recovery Mechanism for Forgotten Password) allows attackers to circumvent the authentication controls of the Daikin Security Gateway. The vulnerability is network-accessible, meaning attackers can exploit it remotely without any prior authentication or user interaction. The flaw resides in how the system handles user-controlled keys during the authentication process, enabling complete bypass of credential verification.

The impact of successful exploitation includes unauthorized access to gateway functions, potential manipulation of connected building automation and HVAC systems, and disruption of critical infrastructure operations. Given that Daikin Security Gateways are commonly deployed in industrial and commercial environments, exploitation could have cascading effects on building management systems.

Root Cause

The root cause is a weak password recovery mechanism combined with improper handling of user-controlled keys. The authentication system fails to properly validate key parameters supplied by users, allowing attackers to manipulate these values to bypass the intended authentication flow. This represents a fundamental design flaw in how the gateway processes authentication requests.

Attack Vector

The attack is executed over the network with low complexity. An attacker does not need any privileges or user interaction to exploit this vulnerability. The attack sequence involves:

The attacker identifies an exposed Daikin Security Gateway on the network
Crafted requests are sent that manipulate user-controlled key parameters
The authentication mechanism improperly processes the malformed keys
The attacker gains unauthorized access to the system without valid credentials

Due to the nature of this vulnerability involving authentication bypass through manipulated keys, specific exploitation typically involves sending specially crafted authentication requests that abuse the weak key validation mechanism. For detailed technical information, refer to the CISA ICS Advisory ICSA-25-254-10.

Detection Methods for CVE-2025-10127

Indicators of Compromise

Unusual authentication attempts or login patterns to Security Gateway interfaces
Access logs showing successful authentications without corresponding valid credential submissions
Unexpected configuration changes to HVAC or building automation systems
Network traffic anomalies targeting the Security Gateway management ports

Detection Strategies

Monitor authentication logs for anomalous access patterns, particularly successful logins without proper credential exchange
Implement network intrusion detection rules to identify malformed authentication requests targeting Daikin Security Gateways
Deploy behavioral analytics to detect unauthorized access to building management system endpoints
Review access control lists and audit trails for unexpected administrative actions

Monitoring Recommendations

Enable verbose logging on all Daikin Security Gateway interfaces
Implement real-time alerting for authentication events, especially from external network sources
Monitor for reconnaissance activity targeting ICS/SCADA environments
Correlate security events across building automation and IT security systems

How to Mitigate CVE-2025-10127

Immediate Actions Required

Isolate affected Daikin Security Gateways from direct internet access
Implement network segmentation to restrict access to trusted internal networks only
Enable multi-factor authentication where supported
Review and restrict administrative access to essential personnel only
Monitor systems for signs of unauthorized access while awaiting patches

Patch Information

Contact Daikin Europe directly through their customer support portal for the latest security patches and firmware updates. Organizations should also review the CISA ICS Advisory ICSA-25-254-10 for official guidance on remediation steps.

Workarounds

Place Security Gateway behind a VPN or secure gateway requiring pre-authentication
Implement IP whitelisting to restrict access to known management stations
Disable remote management interfaces until patches are available
Deploy web application firewall rules to filter malicious authentication requests
Enable audit logging and forward logs to a centralized SIEM for monitoring

bash

# Example network segmentation firewall rule
# Restrict Security Gateway access to management VLAN only
iptables -A INPUT -s 10.10.50.0/24 -d <GATEWAY_IP> -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -d <GATEWAY_IP> -p tcp --dport 443 -j DROP