CVE-2022-26642 in TL-WR840N
Summary
by MITRE • 03/29/2022
TP-LINK TL-WR840N(ES)_V6.20 was discovered to contain a buffer overflow via the X_TP_ClonedMACAddress parameter.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/31/2022
The vulnerability identified as CVE-2022-26642 affects TP-LINK TL-WR840N(ES)_V6.20 routers and represents a critical buffer overflow flaw within the device's web interface handling mechanism. This issue manifests through the X_TP_ClonedMACAddress parameter, which is utilized in the router's configuration management system to process MAC address cloning functionality. The buffer overflow occurs when the system fails to properly validate input length before copying data into fixed-size memory buffers, creating a potential exploitation vector for remote attackers. This vulnerability resides in the router's embedded web server implementation and specifically targets the parameter handling logic that processes user-supplied MAC address values.
The technical exploitation of this buffer overflow vulnerability follows established patterns documented in CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw enables an attacker to craft malicious input containing excessive data in the X_TP_ClonedMACAddress parameter, causing the router's memory management to overflow and potentially overwrite critical program execution structures. This type of vulnerability directly maps to ATT&CK technique T1203, which encompasses exploitation of input validation flaws to achieve arbitrary code execution or system compromise. The vulnerability exists because the router's firmware does not implement proper input sanitization or length validation before processing the MAC address parameter, allowing an attacker to inject malicious data that exceeds the allocated buffer space.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides potential attackers with opportunities to execute arbitrary code on the affected router. Successful exploitation could result in complete system compromise, allowing unauthorized users to gain administrative access to the router configuration, modify network settings, redirect traffic, or establish persistent backdoors. The vulnerability affects the router's web-based management interface, making it accessible to remote attackers without requiring physical access or specialized equipment. Network traffic analysis reveals that the affected parameter is processed through the router's HTTP server component, which handles various configuration parameters including network settings, security configurations, and device management functions. This exposure creates a significant risk for organizations relying on these devices for network infrastructure, as compromised routers can serve as entry points for broader network infiltration or as amplification devices for distributed denial-of-service attacks.
Mitigation strategies for CVE-2022-26642 should prioritize immediate firmware updates from TP-LINK, as the vendor has likely released patches addressing this specific buffer overflow condition. Network administrators should implement network segmentation and access control measures to limit exposure of affected devices to untrusted networks, while monitoring for suspicious traffic patterns that might indicate exploitation attempts. The implementation of input validation controls and parameter sanitization should be enforced at multiple layers including network firewalls, intrusion detection systems, and router configuration management interfaces. Organizations should also consider disabling unnecessary web management interfaces when possible, and implementing network monitoring solutions that can detect anomalous parameter values being submitted to router management interfaces. Regular vulnerability assessments and security audits of network infrastructure should include identification and remediation of similar buffer overflow conditions across all network devices, particularly those with web-based management interfaces that process user-supplied data. The vulnerability highlights the importance of implementing proper software security practices during firmware development, including bounds checking, input validation, and memory management controls that align with industry standards such as those recommended by the Open Web Application Security Project OWASP and the National Institute of Standards and Technology NIST cybersecurity frameworks.