An issue was discovered in Tenda W20E V4.0br_V15.11.0.6. This vulnerability allows attackers to send overly long `addDhcpRules` data. When these rules enter the `addDhcpRule` function and are processed by `ret = sscanf(pRule, " %d\t%[^\t]\t%[^\n\r\t]", &dhcpsIndex, dhcpsIP, dhcpsMac);`, the lack of size validation for the rules could lead to buffer overflows in `dhcpsIndex`, `dhcpsIP`, and `dhcpsMac`.
The CVSS score for this vulnerability is 9.8, indicating a critical severity level. The risk to organizations includes unauthorized access to sensitive information, potential data corruption, and service disruptions. Attackers may leverage this vulnerability to execute arbitrary code or cause denial of service.
Currently, there are no known exploits or public proof of concept available for this vulnerability. However, organizations should prioritize patching immediately to mitigate the risk associated with this critical vulnerability.
With the potential for widespread exploitation, organizations using Tenda W20E firmware must act swiftly. Remediation strategies should be scheduled in priority patch cycles to ensure systems remain secure.
Vulnerability Details
The Tenda W20E firmware version 15.11.0.6 is affected by this vulnerability. The vulnerability type is classified as a buffer overflow, specifically identified by CWE-120. The lack of size validation in the `addDhcpRule` function is the root cause of this issue.
The CVSS vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating that the attack vector is network-based, requires low complexity, and does not require user interaction. The impacts on confidentiality, integrity, and availability are all high.
Technical Analysis
The root cause of this vulnerability lies in the `addDhcpRule` function's processing of input data without proper validation of size. This oversight allows attackers to exploit the system through crafted DHCP rules that exceed expected lengths.
The attack vector is network-based, meaning an attacker can initiate an exploit from a remote location without needing physical access to the device. The attack complexity is low, as no special conditions must be met for an exploit to succeed, and no privileges are required to exploit this vulnerability.
Risk & Impact Analysis
Risk to organizations includes unauthorized access to sensitive information, potential data corruption, and service disruptions. The critical nature of this vulnerability, combined with its exploitation potential, could result in significant impact on organizational operations.
Given its critical CVSS score, organizations must prioritize remediation efforts to prevent exploitation. The urgency of addressing this vulnerability cannot be overstated, as it poses a severe risk to network integrity.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected version of the Tenda W20E firmware is 15.11.0.6. Organizations using this version should prioritize patching to prevent exploitation of this vulnerability.
Mitigation & Remediation
Organizations should update to the latest firmware version provided by Tenda to remediate this vulnerability. To ensure protection, security teams should also consider implementing additional network controls and monitoring for any unusual activity related to DHCP rules.
For detailed guidance on security testing and vulnerability management, organizations may refer to resources like penetration testing best practices.
Detection Guidance
To detect attempts to exploit this vulnerability, organizations should monitor logs for unusual DHCP requests, particularly those with long `addDhcpRules` data. Additionally, behavioral anomalies in network traffic should be investigated.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability highlights the importance of input validation and robust error handling in network devices. Security teams should learn from this incident to enhance their coding practices and review existing systems for similar weaknesses.
For more information on effective vulnerability management, organizations can explore topics such as vulnerability management programs and penetration testing methodology to strengthen their defenses against potential threats.
Organizations should also stay updated on trends in cyber threats, which can be explored in resources like 2026 ransomware targeting trends to remain proactive in their security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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