CVE-2026-36603

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…

High · published June 3, 2026

CVSS v3.1
8.1
EPSS
0%
Percentile
24.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.1 · HIGH
Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00328 · 24.6th percentile
Published
2026-06-03T00:00Z
EPSS history
Timeline
  • 03 JUN 00:00Z
    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…
    cvelistv5