CVE-2026-27754: Sodola SL902 Firmware Auth Bypass Issue

CVE-2026-27754 Overview

CVE-2026-27754 is a weak hash algorithm vulnerability affecting SODOLA SL902-SWTGW124AS network switch firmware. The firmware versions through 200.1.20 use the cryptographically broken MD5 hash function for session cookie generation, significantly weakening session security. Attackers can exploit predictable session tokens combined with MD5's well-documented collision vulnerabilities to forge valid session cookies and gain unauthorized access to the device.

Critical Impact

Successful exploitation allows attackers to forge session cookies and gain unauthorized administrative access to affected network switches, potentially compromising network infrastructure security.

Affected Products

• SODOLA SL902-SWTGW124AS Firmware versions through 200.1.20
• SODOLA SL902-SWTGW124AS Hardware Device

Discovery Timeline

• 2026-02-27 - CVE-2026-27754 published to NVD
• 2026-03-03 - Last updated in NVD database

Technical Details for CVE-2026-27754

Vulnerability Analysis

This vulnerability stems from the use of the MD5 hashing algorithm for session token generation in the device's web management interface. MD5 has been considered cryptographically broken since 2004 when practical collision attacks were demonstrated. The weakness is classified under CWE-328 (Reversible One-Way Hash), indicating the use of a cryptographic hash function that does not meet modern security requirements.

The attack surface is network-accessible, meaning any attacker who can reach the device's web management interface can potentially exploit this vulnerability. The exploitation does not require authentication, making it particularly concerning for devices exposed on network segments accessible to unauthorized users.

Root Cause

The root cause of CVE-2026-27754 is the implementation decision to use MD5 for session cookie generation. MD5 produces a 128-bit hash value and was designed in 1991. Over the years, numerous vulnerabilities have been discovered, including practical collision attacks that allow attackers to generate different inputs that produce the same hash output. When combined with predictable input values used in session token generation, this creates a scenario where attackers can forge valid session cookies without possessing legitimate credentials.

Attack Vector

The attack is network-based and targets the web management interface of the SODOLA SL902-SWTGW124AS switch. An attacker with network access to the device can analyze the session token generation mechanism, identify the predictable components used as input to the MD5 hash, and exploit MD5's collision vulnerabilities to forge valid session tokens.

The vulnerability exploitation flow involves:

1. Network reconnaissance to identify vulnerable SODOLA switches
2. Analysis of session cookie structure and generation patterns
3. Identification of predictable input components (such as timestamps, device identifiers, or sequential values)
4. Computation of forged session tokens using MD5 collision techniques
5. Injection of forged cookies to authenticate as a legitimate user

For detailed technical information regarding the MD5 collision vulnerabilities exploited in this attack, refer to the VulnCheck Security Advisory.

Detection Methods for CVE-2026-27754

Indicators of Compromise

• Unusual or unexpected administrative sessions on affected SODOLA devices
• Multiple concurrent sessions from different IP addresses using similar session tokens
• Authentication events without corresponding login attempts in logs
• Configuration changes made during periods of no legitimate administrative activity

Detection Strategies

• Monitor web management interface access logs for anomalous session patterns
• Implement network traffic analysis to detect reconnaissance activity targeting switch management ports
• Deploy intrusion detection rules to identify MD5 collision attack patterns
• Review session management logs for tokens that appear to be generated outside normal authentication flows

Monitoring Recommendations

• Enable comprehensive logging on all SODOLA switch web management interfaces
• Implement network segmentation to restrict access to device management interfaces
• Deploy SentinelOne Singularity to monitor network traffic patterns and detect unauthorized access attempts
• Establish baseline administrative access patterns to quickly identify deviations

How to Mitigate CVE-2026-27754

Immediate Actions Required

• Restrict network access to the switch web management interface to trusted management networks only
• Implement firewall rules to block unauthorized access to the device's management ports
• Monitor for unauthorized configuration changes on affected devices
• Consider disabling the web management interface if not operationally required and use console access instead

Patch Information

At the time of this writing, no vendor patch has been publicly announced. Organizations should monitor the SODOLA product page and the VulnCheck Security Advisory for firmware updates that address this vulnerability.

Workarounds

• Isolate affected devices on a dedicated management VLAN with strict access controls
• Implement a jump host or bastion server for all management access to vulnerable devices
• Deploy network-level authentication (802.1X) to limit which systems can communicate with the switch management interface
• Consider replacing affected devices with switches that implement modern cryptographic standards for session management

# Example firewall rule to restrict management access (iptables)
# Replace MANAGEMENT_SUBNET with your trusted management network
iptables -A INPUT -p tcp --dport 80 -s MANAGEMENT_SUBNET -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s MANAGEMENT_SUBNET -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP