Security Advisory: http_gdpr_decrypt Pre-Authentication Stack-Based Buffer Overflow (CVE-2026-75118)

Vulnerability and Impact Description:

CVE-2026-75118

A pre-authentication stack-based buffer overflow vulnerability exists in the http_gdpr_decrypt function of TL-MR100 V3.20 due to insufficient bounds checking of encrypted requests to the /cgi/login endpoint. An adjacent unauthenticated attacker with access to the router's web management interface can trigger memory corruption and potentially achieve arbitrary code execution.

Successful exploitation can overwrite saved control-flow data on the httpd process stack prior to authentication, resulting in a service crash or potential arbitrary code execution in the context of the affected process.

CVSS v4.0 Score: 8.7 / High

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Affected Products/Versions and Fixes:

Recommendations:

We strongly recommend that users with affected devices take the following actions:

1. Update affected devices to the latest firmware version that fixed the vulnerability:

EN: Download for TL-MR100 | TP-Link

Note: TL-MR100 is not sold in the US.

Disclaimer:

This advisory is provided for informational purposes only and is subject to change without notice. The information is provided “as is” without warranties of any kind. TP-Link recommends that customers promptly apply available firmware updates or implement documented workarounds as provided in this advisory. Devices/systems that are not updated or mitigated as described may remain vulnerable, and TP-Link disclaims any responsibility or liability for any damages or losses arising from a failure to implement such updates.