CVE-2026-36605Public exploit

Persistent control-plane crash via incomplete HTTP requests

Published Jun 3, 2026 · Updated Jun 3, 2026

Denial of service in the HTTP server of Mercusys AC12G (EU) V1 firmware 200909 and 210128 allows remote attackers to crash the control plane. The server has a small fixed connection pool and no timeout for incomplete requests, so approximately 50 connections with unfinished HTTP headers exhaust every slot. Access to the router's LAN is required; HTTP and UPnP remain unresponsive until a physical power cycle, while routing and DNS continue operating.

CVSS severity6.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in the HTTP server of Mercusys AC12G (EU) V1 firmware 200909 and 210128 allows remote attackers to crash the control plane. The server has a small fixed connection pool and no timeout for incomplete requests, so approximately 50 connections with unfinished HTTP headers exhaust every slot. Access to the router's LAN is required; HTTP and UPnP remain unresponsive until a physical power cycle, while routing and DNS continue operating.

The record

CVE
CVE-2026-36605
Published
Jun 3, 2026
Updated
Jun 3, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo