CVE-2026-6239
Authenticated Stack-based Buffer Overflow in ONVIF CreateUsers Service in TP-Link Tao C520WS
Description
A stack‑based buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where the device fails to properly validate the number of XML user nodes during request processing. An authenticated attacker can send a specially crafted ONVIF request containing an excessive number of user entries to trigger memory corruption. Successful exploitation may cause the ONVIF management service to terminate unexpectedly, resulting in a denial‑of‑service (DoS) condition that disrupts device configuration and management functions.
INFO
Published Date :
June 6, 2026, 12:16 a.m.
Last Modified :
July 23, 2026, 7:10 a.m.
Remotely Exploit :
No
Source :
f23511db-6c3e-4e32-a477-6aa17d310630
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | f23511db-6c3e-4e32-a477-6aa17d310630 | ||||
| CVSS 4.0 | MEDIUM | f23511db-6c3e-4e32-a477-6aa17d310630 |
Solution
- Apply the latest firmware update provided by the vendor.
- Validate ONVIF user node count in requests.
- Monitor device for unexpected service terminations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6239.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6239 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6239
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6239 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6239 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Jul. 23, 2026
Action Type Old Value New Value Added Translation Title: Tapo C520WS v2 de TP-Link Systems, Description: Una vulnerabilidad de desbordamiento de búfer basado en pila existe en Tapo C520WS v2 en el servicio ONVIF CreateUsers, donde el dispositivo no valida correctamente el número de nodos de usuario XML durante el procesamiento de solicitudes. Un atacante autenticado puede enviar una solicitud ONVIF especialmente diseñada que contiene un número excesivo de entradas de usuario para desencadenar la corrupción de memoria. La explotación exitosa puede hacer que el servicio de gestión ONVIF termine inesperadamente, lo que resulta en una condición de denegación de servicio (DoS) que interrumpe las funciones de configuración y gestión del dispositivo. -
CVE Modified by f23511db-6c3e-4e32-a477-6aa17d310630
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'TP-Link Systems Inc.', 'product': 'Tapo C520WS v2', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.2.6 Build 260528', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-6239', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-08T13:07:25.793532Z'} -
New CVE Received by f23511db-6c3e-4e32-a477-6aa17d310630
Jun. 06, 2026
Action Type Old Value New Value Added Description A stack‑based buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where the device fails to properly validate the number of XML user nodes during request processing. An authenticated attacker can send a specially crafted ONVIF request containing an excessive number of user entries to trigger memory corruption. Successful exploitation may cause the ONVIF management service to terminate unexpectedly, resulting in a denial‑of‑service (DoS) condition that disrupts device configuration and management functions. Added CVSS V4.0 AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-121 Added Reference https://www.tp-link.com/en/support/download/tapo-c520ws/#Firmware-Release-Notes Added Reference https://www.tp-link.com/us/support/download/tapo-c520ws/#Firmware-Release-Notes Added Reference https://www.tp-link.com/us/support/faq/5120/