Is CVE-2026-36608 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-36608 being exploited in the wild.

How severe is CVE-2026-36608?

Informational severity, with a CVSS score of 9.6, published 3 June 2026.

Which products and versions are affected?

Mercusys AC12G AC12G(EU)_V1_200909, AC12G(EU)_V1_210128.

Is there a fix for CVE-2026-36608?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-36608 attacked?

It is attacked from the adjacent network, in a network appliance.

Am I affected by CVE-2026-36608?

Check whether you run Mercusys AC12G at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-36608: Mercusys AC12G UPnP port forwarding to local admin interface

CVE-2026-36608 · Severity: info · CVSS 9.6 · Published 2026-06-03

The Mercusys AC12G router contains a security flaw that allows its internal management dashboard to be exposed to the public internet. By sending a single command from within the local network, an attacker can bypass security restrictions and make the router's login page accessible to anyone globally. This significantly increases the risk of unauthorized access, remote takeover, and potential network compromise, especially as the device is reportedly end-of-life and may not receive a fix.

Technologies: Mercusys AC12G. Vendors: Mercusys.

Quick answers

Is CVE-2026-36608 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-36608 being exploited in the wild.
How severe is CVE-2026-36608?: Informational severity, with a CVSS score of 9.6, published 3 June 2026.
Which products and versions are affected?: Mercusys AC12G AC12G(EU)_V1_200909, AC12G(EU)_V1_210128.
Is there a fix for CVE-2026-36608?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-36608 attacked?: It is attacked from the adjacent network, in a network appliance.
Am I affected by CVE-2026-36608?: Check whether you run Mercusys AC12G at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in the UPnP IGD AddPortMapping action due to insufficient validation of the NewInternalClient parameter. An unauthenticated attacker on the local network (LAN) can submit a SOAP request specifying the router's own LAN IP (192.168.1.1) or localhost (127.0.0.1) as the internal client. This creates a port forwarding rule that maps a WAN-side port to the router's internal HTTP admin interface (typically port 80). When combined with other vulnerabilities like a lack of rate limiting, this allows for remote brute-force attacks against the admin credentials from the internet. The device is reportedly end-of-life, and no official patch is expected.

Affected products

Mercusys AC12G (EU) V1 AC12G(EU)_V1_200909, AC12G(EU)_V1_210128

Timeline

2026-06-03: disclosed
2026-06-03: advisory

References

https://github.com/Tymbark7372/MERCUSYS-AC12G/blob/master/advisories/CVE-2026-36608.md

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