Is CVE-2026-36605 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-36605 being exploited in the wild.

How severe is CVE-2026-36605?

Informational severity, with a CVSS score of 7.5, 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-2026-36605?

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-2026-36605 attacked?

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

Am I affected by CVE-2026-36605?

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-2026-36605: Mercusys AC12G HTTP denial of service in web management interface

CVE-2026-36605 · Severity: info · CVSS 7.5 · Published 2026-06-03

The Mercusys AC12G router is vulnerable to a denial-of-service attack that disables its management interface. An attacker on the local network can send a small number of incomplete web requests to the device, causing the administration panel and UPnP services to crash permanently. While basic internet routing continues to function, the administrator will be locked out of the settings and cannot recover access without physically unplugging and restarting the router.

Technologies: Mercusys AC12G. Vendors: Mercusys.

Quick answers

Is CVE-2026-36605 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-36605 being exploited in the wild.
How severe is CVE-2026-36605?: Informational severity, with a CVSS score of 7.5, 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-2026-36605?: 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-2026-36605 attacked?: It is attacked from the adjacent network, in a network appliance.
Am I affected by CVE-2026-36605?: 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 Mercusys AC12G (EU) V1 router's HTTP server (port 80) and UPnP service (port 1900) are vulnerable to uncontrolled resource consumption (CWE-400). The HTTP server utilizes a small, fixed connection pool and fails to implement timeouts for incomplete requests. An attacker on the adjacent network can exhaust all available connection slots by opening approximately 50 concurrent TCP connections with slow or incomplete HTTP headers. This results in a persistent crash of the control plane; while the data plane (routing and DNS) remains operational, the web management interface becomes permanently unresponsive. No automatic recovery or watchdog timer is present, necessitating a physical power cycle. The product is reportedly end-of-life with no planned fix.

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-2026-36605.md

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