CVE-2025-13901: Machine Expert Protocol DoS Vulnerability

CVE-2025-13901 Overview

CVE-2025-13901 is an Improper Resource Shutdown or Release vulnerability (CWE-404) that affects Schneider Electric's Machine Expert protocol. This vulnerability enables an unauthenticated attacker to cause a partial Denial of Service condition by sending malicious payloads designed to occupy active communication channels.

The vulnerability exists due to improper handling of resource release when communication channels are exhausted. An attacker exploiting this flaw can monopolize available protocol channels, degrading service availability for legitimate users and potentially disrupting industrial control operations.

Critical Impact

Unauthenticated attackers can cause partial Denial of Service on Machine Expert protocol by exhausting communication channels, potentially affecting industrial control system operations.

Affected Products

• Schneider Electric Machine Expert Protocol implementations
• Industrial control systems utilizing the affected protocol
• Associated SCADA/ICS infrastructure

Discovery Timeline

• 2026-03-10 - CVE CVE-2025-13901 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2025-13901

Vulnerability Analysis

This vulnerability stems from improper resource management within the Machine Expert protocol implementation. When the protocol receives incoming connections or requests, it allocates communication channels to handle those sessions. The flaw occurs because the system fails to properly release or timeout these channel resources when they are no longer in active legitimate use.

An unauthenticated attacker can exploit this weakness by sending specially crafted network payloads that cause the protocol handler to allocate communication channels without proper cleanup. As channels become occupied and unavailable, legitimate users experience degraded service or inability to establish new connections.

The network-accessible nature of this vulnerability means that remote attackers can target affected systems without requiring any prior authentication or user interaction. The impact is limited to availability degradation rather than data compromise, resulting in a partial denial of service condition.

Root Cause

The root cause is classified as CWE-404: Improper Resource Shutdown or Release. The Machine Expert protocol implementation does not adequately manage the lifecycle of communication channel resources. Specifically, the code path handling incoming connections fails to implement proper cleanup mechanisms, timeout policies, or resource limits that would prevent channel exhaustion attacks.

This allows an attacker to hold channels open indefinitely or create orphaned channel allocations that consume system resources without being properly released back to the available pool.

Attack Vector

The attack is conducted over the network against the Machine Expert protocol endpoint. An unauthenticated attacker sends malformed or specially crafted payloads that trigger the resource allocation flaw. The attack does not require any user interaction or prior access to the system.

The attacker's malicious payloads are designed to occupy active communication channels without proper session termination. By repeatedly sending these payloads, the attacker can progressively exhaust available channels until legitimate communications are impacted. The partial nature of the denial of service suggests that not all system functionality is affected, but protocol-dependent operations experience degradation or unavailability.

Detection Methods for CVE-2025-13901

Indicators of Compromise

• Unusual volume of incomplete or malformed connection attempts to Machine Expert protocol ports
• Communication channel exhaustion alerts or resource allocation failures in system logs
• Degraded response times or connection timeouts for legitimate Machine Expert protocol communications
• Multiple connection attempts from single source addresses without proper session completion

Detection Strategies

• Monitor network traffic for anomalous patterns targeting Machine Expert protocol endpoints
• Implement connection rate limiting and track sources exceeding normal connection thresholds
• Configure alerts for communication channel resource utilization approaching capacity limits
• Deploy network intrusion detection signatures for known resource exhaustion attack patterns

Monitoring Recommendations

• Enable detailed logging on systems running Machine Expert protocol to capture connection lifecycle events
• Implement baseline monitoring of normal communication channel utilization to detect anomalies
• Monitor for repeated connection attempts that do not complete normal handshake sequences
• Track system resource metrics including memory and channel pool allocation on affected devices

How to Mitigate CVE-2025-13901

Immediate Actions Required

• Review the Schneider Electric Security Notice SEVD-2026-069-01 for vendor-specific guidance
• Restrict network access to Machine Expert protocol endpoints to authorized IP addresses only
• Implement network segmentation to isolate industrial control systems from untrusted networks
• Enable connection rate limiting on network devices protecting affected systems

Patch Information

Schneider Electric has published a security notice addressing this vulnerability. Administrators should consult the Schneider Electric Security Notice SEVD-2026-069-01 for specific patch availability, version information, and update instructions.

Apply any available firmware or software updates as directed by the vendor security advisory. Ensure updates are tested in a non-production environment before deployment to critical infrastructure systems.

Workarounds

• Implement strict firewall rules to limit access to Machine Expert protocol ports from trusted networks only
• Deploy network-based rate limiting to prevent connection flood attacks against affected services
• Configure session timeout policies on network devices to automatically terminate idle or incomplete connections
• Consider placing affected systems behind a VPN or other authenticated access mechanism to reduce attack surface

# Example firewall configuration to restrict Machine Expert protocol access
# Adjust port numbers and IP ranges according to your environment

# Allow connections only from trusted management network
iptables -A INPUT -p tcp --dport <machine_expert_port> -s 10.0.0.0/24 -j ACCEPT

# Rate limit new connections to prevent channel exhaustion
iptables -A INPUT -p tcp --dport <machine_expert_port> -m connlimit --connlimit-above 10 -j DROP

# Drop all other traffic to the protocol port
iptables -A INPUT -p tcp --dport <machine_expert_port> -j DROP