CVE-2025-56752: Ruijie RG-ES228GS-P Auth Bypass Flaw

CVE-2025-56752 Overview

A critical authentication bypass vulnerability has been identified in the Ruijie RG-ES series network switch firmware. This vulnerability affects firmware version ESW_1.0(1)B1P39 and related versions, enabling remote attackers to completely bypass authentication mechanisms on the affected devices. By sending crafted HTTP POST requests to the /user.cgi endpoint, attackers can gain unrestricted access to administrative settings and potentially seize full control of the affected network switches.

The Ruijie RG-ES series switches are widely deployed in enterprise networks, small-to-medium businesses, and industrial environments for network infrastructure management. This authentication bypass vulnerability poses a significant threat to network security as it allows unauthenticated attackers to modify switch configurations, potentially leading to network traffic interception, denial of service, or lateral movement within compromised networks.

Critical Impact

Remote attackers can fully bypass authentication and gain administrative control over affected Ruijie network switches without any credentials, enabling complete device takeover and network infrastructure compromise.

Affected Products

• Ruijie RG-ES228GS-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES209GC-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES205GC-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES205GC (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES208GC (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES206GS-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES210GS-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES218GC-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35)
• Ruijie RG-ES226GC-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35)
• Ruijie RG-ES216GC-V2 (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES224GC-V2 (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-ES220GS-P (Firmware versions ESW_1.0(1)B1P27, ESW_1.0(1)B1P35, ESW_1.0(1)B1P39)
• Ruijie RG-NIS2100-8GT2SFP-HP (Firmware version ESW_1.0(1)B1P39)
• Ruijie RG-NIS2100-4GT2SFP-HP (Firmware version ESW_1.0(1)B1P39)
• Ruijie RG-ES206MG-P (Firmware version ESW_1.0(1)B1P42_RELEASE(12142711))
• Ruijie RG-ES209MG-P (Firmware version ESW_1.0(1)B1P42_RELEASE(12142711))

Discovery Timeline

• September 3, 2025 - CVE-2025-56752 published to NVD
• September 29, 2025 - Last updated in NVD database

Technical Details for CVE-2025-56752

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287: Improper Authentication) exists in the web management interface of Ruijie RG-ES series switches. The vulnerability allows remote attackers to bypass the authentication mechanism entirely by sending specially crafted HTTP POST requests to the /user.cgi endpoint on the device's web interface.

The web-based management interface of these switches fails to properly validate authentication credentials before processing administrative requests. This flaw enables attackers to access privileged functionality without providing valid credentials, effectively treating unauthenticated requests as if they originated from an authenticated administrator.

The attack can be executed remotely over the network without requiring any prior authentication or user interaction. Once exploited, attackers gain the ability to modify critical device configurations, access sensitive network data, and potentially pivot to other network segments.

Root Cause

The root cause of this vulnerability lies in improper authentication validation within the /user.cgi CGI handler. The firmware fails to enforce proper session validation and authentication checks before processing HTTP POST requests to this endpoint. This implementation flaw allows attackers to craft requests that bypass the intended authentication flow, gaining direct access to administrative functions.

The authentication logic appears to trust certain request parameters or headers without adequately verifying that the requesting entity has been properly authenticated through the normal login process. This represents a fundamental breakdown in the access control mechanism of the device's web interface.

Attack Vector

The vulnerability is exploited through the network by sending malicious HTTP POST requests directly to the /user.cgi endpoint on the switch's web management interface. The attack does not require any authentication, user interaction, or prior access to the target device.

An attacker with network access to the management interface of a vulnerable Ruijie switch can exploit this vulnerability by crafting HTTP POST requests with specific parameters that bypass authentication checks. Upon successful exploitation, the attacker gains full administrative access to the switch, enabling them to:

• Modify switch configurations (VLANs, port settings, ACLs)
• Create new administrative accounts
• Access or modify network traffic
• Disable security features
• Use the compromised device as a pivot point for further attacks

For technical details on the exploitation methodology, refer to the GitHub vulnerability research documentation.

Detection Methods for CVE-2025-56752

Indicators of Compromise

• Unusual HTTP POST requests to /user.cgi endpoint from unauthorized IP addresses
• Administrative configuration changes without corresponding legitimate administrator logins
• Creation of new user accounts or modification of existing credentials without authorization
• Unexpected modifications to switch configurations such as VLAN settings, ACLs, or port configurations
• Web server access logs showing repeated requests to /user.cgi from external or suspicious sources

Detection Strategies

• Deploy network intrusion detection systems (IDS/IPS) with signatures to detect anomalous HTTP POST requests to /user.cgi on Ruijie switch management interfaces
• Implement web application firewall (WAF) rules to monitor and block suspicious requests targeting CGI endpoints on network infrastructure devices
• Configure SIEM rules to correlate authentication events with configuration changes on Ruijie switches, alerting on changes without preceding successful authentication
• Enable and centralize logging from all Ruijie switches to detect unauthorized access attempts and configuration modifications

Monitoring Recommendations

• Enable comprehensive logging on all Ruijie RG-ES series switches and forward logs to a centralized SIEM platform for analysis
• Implement network traffic analysis to monitor HTTP traffic to switch management interfaces, particularly POST requests to authentication-related endpoints
• Establish baseline configurations for all switches and implement automated configuration drift detection to identify unauthorized changes
• Monitor for new user account creation or privilege modifications on network infrastructure devices

How to Mitigate CVE-2025-56752

Immediate Actions Required

• Restrict access to switch management interfaces by implementing network segmentation and ACLs to limit access to trusted administrative networks only
• Disable web-based management interfaces if not required and use alternative management methods such as SSH or console access
• Implement strict firewall rules to block external access to switch management ports (typically HTTP/HTTPS on ports 80/443)
• Audit all Ruijie RG-ES series switches for signs of compromise, including unauthorized configuration changes or new user accounts
• Contact Ruijie Networks support to inquire about firmware updates addressing this vulnerability

Patch Information

As of the last NVD update on September 29, 2025, no vendor patch has been publicly documented for this vulnerability. Organizations should monitor Ruijie Networks official support channels and security advisories for firmware updates that address CVE-2025-56752. In the interim, apply the recommended workarounds to reduce exposure.

For the latest information on this vulnerability, refer to the GitHub CVE-2025-56752 Research documentation.

Workarounds

• Implement network segmentation to isolate switch management interfaces from untrusted networks and the general user network
• Deploy access control lists (ACLs) on upstream devices to restrict access to switch management IPs to specific authorized administrator workstations
• Disable the web management interface and use SSH or serial console for switch administration where possible
• Place switch management interfaces on a dedicated out-of-band management VLAN with strict access controls
• Implement 802.1X or MAC-based authentication on ports connecting to switch management networks

# Example ACL configuration for upstream router/firewall
# Restrict access to switch management network (example: 10.0.100.0/24)

# Allow access only from administrator workstation (10.1.1.100)
iptables -A FORWARD -s 10.1.1.100/32 -d 10.0.100.0/24 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -s 10.1.1.100/32 -d 10.0.100.0/24 -p tcp --dport 443 -j ACCEPT

# Deny all other access to switch management network web interfaces
iptables -A FORWARD -d 10.0.100.0/24 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 10.0.100.0/24 -p tcp --dport 443 -j DROP