CVE-2025-41655: Unauthenticated DOS Vulnerability

CVE-2025-41655 Overview

CVE-2025-41655 is a Missing Authentication for Critical Function (CWE-306) vulnerability that allows an unauthenticated remote attacker to access a specific URL endpoint, causing the affected device to reboot. This authentication bypass vulnerability enables denial of service attacks against the target system without requiring any credentials or user interaction.

Critical Impact

Remote attackers can repeatedly trigger device reboots, causing persistent denial of service and disrupting operations without any authentication requirements.

Affected Products

• Affected products are specified in the CERT@VDE Security Advisory VDE-2025-011

Discovery Timeline

• 2025-05-26 - CVE-2025-41655 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-41655

Vulnerability Analysis

This vulnerability represents a critical authentication control failure where sensitive device management functionality is exposed to unauthenticated users. The affected device contains a web interface with an administrative endpoint that triggers a device reboot. Due to missing authentication checks on this endpoint, any network-accessible attacker can invoke this functionality without providing credentials.

The vulnerability is classified under CWE-306 (Missing Authentication for Critical Function), which describes scenarios where software does not perform authentication for functionality that requires a provable user identity. In this case, the reboot functionality should only be accessible to authenticated administrators, but the lack of proper access controls allows anyone with network access to exploit it.

The attack can be executed remotely over the network with low complexity and requires no privileges or user interaction. While the vulnerability does not impact confidentiality or integrity, it poses a significant availability threat as attackers can repeatedly trigger device reboots to maintain a denial of service condition.

Root Cause

The root cause is the absence of authentication verification before executing the device reboot function. The vulnerable endpoint fails to validate that the requesting user has proper administrative privileges before processing the reboot command. This represents a fundamental access control design flaw where critical functionality is left unprotected.

Attack Vector

The attack leverages network access to reach the vulnerable web interface endpoint. An attacker simply needs to craft an HTTP request to the specific URL that triggers the reboot functionality. Since no authentication is required, the attack can be performed by anyone with network visibility to the target device.

The attack is particularly concerning because:

• It requires no special privileges or credentials
• No user interaction is needed
• The attack can be automated for persistent denial of service
• Multiple devices can be targeted simultaneously

Detection Methods for CVE-2025-41655

Indicators of Compromise

• Unusual HTTP requests to device management endpoints from untrusted sources
• Repeated device reboots occurring at irregular intervals without administrative action
• Network traffic patterns showing requests to known vulnerable URL paths
• Log entries indicating reboot commands without corresponding authentication events

Detection Strategies

• Monitor web server access logs for requests to administrative endpoints without preceding authentication
• Implement network intrusion detection rules to identify requests targeting the vulnerable URL path
• Track device uptime and reboot frequency to detect anomalous restart patterns
• Deploy application-layer firewalls to inspect and alert on suspicious administrative requests

Monitoring Recommendations

• Enable comprehensive logging on affected devices to capture all HTTP requests
• Configure alerting for device reboot events that occur outside maintenance windows
• Monitor network traffic for repeated connections to device management interfaces from external sources
• Establish baseline device uptime metrics to identify deviation patterns

How to Mitigate CVE-2025-41655

Immediate Actions Required

• Review the CERT@VDE Security Advisory VDE-2025-011 for vendor-specific guidance
• Restrict network access to the device management interface using firewall rules
• Place affected devices behind a VPN or network segmentation to limit exposure
• Implement web application firewall rules to block access to the vulnerable endpoint

Patch Information

Refer to the CERT@VDE Security Advisory VDE-2025-011 for official patch information and updates from the vendor. Organizations should prioritize applying vendor-provided patches as they become available.

Workarounds

• Implement network-level access controls to restrict administrative interface access to trusted IP addresses
• Deploy a reverse proxy with authentication to protect the vulnerable endpoint
• Disable or block access to the vulnerable URL path if not required for operations
• Consider taking affected devices offline until patches are available in critical environments

# Example network access restriction (adjust for your environment)
# Block external access to device management interface
iptables -A INPUT -p tcp --dport 80 -s ! 10.0.0.0/8 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 10.0.0.0/8 -j DROP