CVE-2024-39769 in AC3000
Summary
by MITRE • 01/14/2025
Multiple buffer overflow vulnerabilities exist in the internet.cgi set_qos() functionality of Wavlink AC3000 M33A8.V5030.210505. A specially crafted HTTP request can lead to stack-based buffer overflow. An attacker can make an authenticated HTTP request to trigger these vulnerabilities.This vulnerability exists in the `cli_mac` POST parameter.
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Analysis
by VulDB Data Team • 08/22/2025
The vulnerability identified as CVE-2024-39769 represents a critical stack-based buffer overflow within the internet.cgi set_qos() functionality of Wavlink AC3000 M33A8.V5030.210505 firmware. This issue manifests when processing HTTP requests containing maliciously crafted data in the cli_mac POST parameter, which serves as the primary attack vector for exploitation. The buffer overflow occurs due to inadequate input validation and bounds checking within the firmware's web interface handling mechanism, creating a pathway for arbitrary code execution and system compromise.
The technical implementation of this vulnerability stems from improper memory management practices within the set_qos function, where the cli_mac parameter is processed without sufficient boundary checks. When an authenticated attacker submits a specially crafted HTTP request containing excessive data in the cli_mac field, the application fails to validate the input length against the allocated buffer space, resulting in memory corruption that can overwrite adjacent stack variables and potentially executable code. This type of vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified under the broader category of CWE-787 Out-of-bounds Write, indicating the severity and attack surface of the flaw.
From an operational perspective, the impact of this vulnerability extends beyond simple denial of service conditions to encompass full system compromise capabilities. An attacker who has already gained authentication credentials can leverage this vulnerability to execute arbitrary code with the privileges of the web server process, potentially leading to complete device takeover, data exfiltration, or use as a pivot point for attacking other devices within the network. The authenticated nature of the attack means that the vulnerability requires legitimate user credentials to exploit, but once accessed, it can provide attackers with persistent access to the device's network configuration and potentially broader network infrastructure. This aligns with ATT&CK technique T1078 Valid Accounts, where adversaries use legitimate credentials to gain access to systems, combined with T1059 Command and Scripting Interpreter for executing malicious commands.
The mitigation strategies for CVE-2024-39769 should prioritize immediate firmware updates from Wavlink to address the underlying buffer overflow conditions. Network administrators should implement strict access controls and monitor for unauthorized authentication attempts, while also considering network segmentation to limit the potential impact of successful exploitation. Additionally, implementing web application firewalls and input validation mechanisms can provide additional layers of protection against similar vulnerabilities in the web interface. Organizations should also conduct thorough vulnerability assessments of their network infrastructure to identify other potentially affected devices running similar firmware versions, as this vulnerability may exist in other Wavlink products within the same product line. The remediation process must include comprehensive testing of the firmware update to ensure that the buffer overflow conditions are properly addressed without introducing new functionality that could create additional security risks.