CVE-2026-24112

Comprehensive Technical Analysis of CVE-2026-24112

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2026-24112 CVSS Score: 9.8

The vulnerability in question is a buffer overflow issue discovered in Tenda W20E V4.0br_V15.11.0.6. The high CVSS score of 9.8 indicates a critical severity level. This score is likely due to the potential for remote code execution, which can lead to complete system compromise. The lack of size validation when processing the userInfo parameter with sscanf in the addWewifiWhiteUser function is the root cause of this vulnerability.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker can remotely exploit this vulnerability by sending a specially crafted request to the affected device.
• Network-Based Attack: Given that the device is a wireless router, the attack can be conducted over the network, making it accessible to a wide range of potential attackers.

Exploitation Methods:

• Buffer Overflow: By crafting a userInfo parameter that exceeds the allocated buffer size, an attacker can overwrite adjacent memory, potentially leading to arbitrary code execution.
• Code Injection: If the attacker can inject malicious code into the overflowed buffer, they can gain control over the device.

3. Affected Systems and Software Versions

Affected Systems:

• Tenda W20E wireless routers running firmware version V4.0br_V15.11.0.6.

Software Versions:

• Specifically, the vulnerability is present in the addWewifiWhiteUser function within the firmware version mentioned above.

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Firmware Update: Users should immediately update their Tenda W20E routers to the latest firmware version provided by the manufacturer.
• Network Segmentation: Isolate the affected device from critical network segments to limit potential damage.
• Firewall Rules: Implement strict firewall rules to restrict access to the device's management interface.

Long-Term Mitigation:

• Regular Patching: Ensure that all network devices are regularly updated with the latest security patches.
• Intrusion Detection Systems (IDS): Deploy IDS to monitor for suspicious activities that may indicate an exploitation attempt.
• Security Audits: Conduct regular security audits and vulnerability assessments on all network devices.

5. Impact on Cybersecurity Landscape

The discovery of this vulnerability highlights the ongoing challenge of securing IoT and network devices. The potential for remote code execution in a widely used consumer device underscores the need for robust security practices in firmware development. This vulnerability could be exploited in large-scale attacks, affecting both individual users and organizations that rely on such devices for network connectivity.

6. Technical Details for Security Professionals

Vulnerability Details:

• Function: addWewifiWhiteUser
• Parameter: userInfo
• Issue: Lack of size validation when processing userInfo with sscanf
• Consequence: Buffer overflow leading to potential arbitrary code execution

Exploitation Steps:

1. Identify Target: Locate a Tenda W20E router running the vulnerable firmware version.
2. Craft Payload: Create a payload that exceeds the buffer size allocated for userInfo.
3. Send Request: Send the crafted payload to the device, targeting the addWewifiWhiteUser function.
4. Gain Control: If successful, the attacker can execute arbitrary code on the device.

Detection and Response:

• Log Analysis: Monitor logs for unusual activities related to the addWewifiWhiteUser function.
• Behavioral Analysis: Use behavioral analysis tools to detect anomalous behavior that may indicate an exploitation attempt.
• Incident Response: Have an incident response plan in place to quickly address and mitigate any successful exploitation.

References:

• GitHub Repository
• Tenda Official Advisory

By addressing this vulnerability promptly and implementing robust security measures, organizations and individuals can significantly reduce the risk of exploitation and ensure the integrity of their network infrastructure.