CVE-2024-39803
Published: 14 January 2025
Summary
CVE-2024-39803 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Wavlink Wl-Wn533A8 Firmware. Its CVSS base score is 9.1 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 24.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
Multiple buffer overflow vulnerabilities, including one in the `sel_mode` POST parameter, exist in the `qos.cgi` `qos_settings()` functionality of the Wavlink AC3000 router running firmware version M33A8.V5030.210505. These flaws allow a specially crafted HTTP request to trigger a stack-based buffer overflow, classified under CWE-120. The vulnerability carries a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H), indicating critical severity due to its potential for high-impact exploitation across confidentiality, integrity, and availability.
An attacker with high-privilege authenticated access (PR:H) can exploit these vulnerabilities remotely over the network (AV:N) with low complexity (AC:L). By sending a malicious HTTP request to the affected `qos.cgi` endpoint, the attacker triggers the stack-based buffer overflow in `qos_settings()`, potentially leading to arbitrary code execution, full system compromise, or denial of service, with scope expanded to changed components (S:C).
Mitigation details are outlined in the Talos Intelligence advisory (TALOS-2024-2049), available at https://talosintelligence.com/vulnerability_reports/TALOS-2024-2049. Security practitioners should consult this report for vendor-specific patch information or workarounds, such as restricting access to the `qos.cgi` endpoint or upgrading firmware if available.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-38347
Vulnerability details
Multiple buffer overflow vulnerabilities exist in the qos.cgi qos_settings() 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.A buffer overflow vulnerability…
more
exists in the `sel_mode` POST parameter.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in public-facing router web CGI (qos.cgi) directly enables remote exploitation for arbitrary code execution.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requires validation of inputs like the 'sel_mode' POST parameter to prevent stack-based buffer overflows in qos.cgi qos_settings().
Mandates timely flaw remediation through firmware patching to eliminate the buffer overflow vulnerability in the Wavlink AC3000 router.
Enforces memory protection mechanisms such as stack canaries or non-executable stacks to mitigate exploitation of the stack-based buffer overflow.