What’s Vulnerable › Vulnerabilities

CVE-2026-6240: Authenticated Stack-based Buffer Overflow in ONVIF DeleteUsers Service on TP-Link Tapo C520WS

• Severity: medium (CVSS 6.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-06 · updated 2026-07-23
• Weakness: CWE-121

Description

A stack-based buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF DeleteUsers service, due to insufficient boundary checks when handling multiple user deletion parameters. An authenticated attacker can send a crafted malicious request containing an excessive number of identifiers to overflow stack memory. Successful exploitation may result in a service crash or deadlock, leading to DoS affecting device management and monitoring functionality.

Affected products

• TP-Link Systems Inc. Tapo C520WS v2: before 1.2.6 Build 260528 — fixed in 1.2.6 Build 260528

How to fix

Upgrade to a fixed version: TP-Link Systems Inc. Tapo C520WS v2 1.2.6 Build 260528. Check the vendor advisory for mitigations.

References

• https://www.tp-link.com/en/support/download/tapo-c520ws/#Firmware-Release-Notes
• https://www.tp-link.com/us/support/download/tapo-c520ws/#Firmware-Release-Notes
• https://www.tp-link.com/us/support/faq/5120/

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