VDB-368189 · CVE-2026-36604 · GCVE-0-2026-36604

Mercusys AC12G HTTP Host Header cross-domain policy

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.2	$0-$5k	2.94

Summaryinfo

A vulnerability has been found in Mercusys AC12G and classified as problematic. This affects an unknown function of the component HTTP Host Header Handler. The manipulation leads to cross-domain policy. This vulnerability is traded as CVE-2026-36604. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Mercusys AC12G (the affected version unknown). It has been rated as problematic. This issue affects an unknown part of the component HTTP Host Header Handler. The manipulation with an unknown input leads to a cross-domain policy vulnerability. Using CWE to declare the problem leads to CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. Impacted is integrity. The summary by CVE is:

Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 does not validate the HTTP Host header, enabling DNS rebinding attacks. An external attacker can rebind a domain to the router's internal IP address, extending the CORS wildcard vulnerability (Access-Control-Allow-Origin: *) to internet-originated attacks.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-36604 since 04/06/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/03/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Mercusys

Name

AC12G

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross-domain policy
CWE: CWE-942 / CWE-346 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/06/2026 CVE reserved
06/03/2026 +58 days Advisory disclosed
06/03/2026 +0 days VulDB entry created
06/03/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Not defined

CVE: CVE-2026-36604 (🔒)
GCVE (CVE): GCVE-0-2026-36604
GCVE (VulDB): GCVE-100-368189

Entryinfo

Created: 06/03/2026 21:39
Changes: 06/03/2026 21:39 (52)
Complete: 🔍
Cache ID: 216::103