CVE-2026-36603

high

Description

Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 exposes 15 of 18 UPnP IGD actions without authentication on port 1900, including AddPortMapping and GetExternalIPAddress. UPnP is enabled by default through the admin interface, allowing any unauthenticated LAN device to create arbitrary port forwarding rules and access WAN traffic statistics.

References

https://github.com/Tymbark7372/MERCUSYS-AC12G/blob/master/advisories/CVE-2026-36603.md

Details

Source: Mitre, NVD

Published: 2026-06-03

Updated: 2026-06-05

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 8.1

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: High

EPSS

EPSS: 0.00022