Mercusys AC12G Admin Interface AddPortMapping/GetExternalIPAddress Remote Code Execution

CVSS Meta Temp Score
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Current Exploit Price (≈)
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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.
8.5$0-$5k2.20

Summaryinfo

A vulnerability was found in Mercusys AC12G. It has been declared as very critical. Affected by this vulnerability is the function AddPortMapping/GetExternalIPAddress of the component Admin Interface. Such manipulation leads to Remote Code Execution. This vulnerability is uniquely identified as CVE-2026-36603. The attack can only be initiated within the local network. No exploit exists.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Mercusys AC12G (version now known). Affected by this issue is the function AddPortMapping/GetExternalIPAddress of the component Admin Interface. The manipulation with an unknown input leads to a remote code execution vulnerability. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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 advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-36603 since 04/06/2026. The exploitation is known to be easy. Access to the local network is required for this attack to succeed. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (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.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

Name

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.5

VulDB Base Score: 8.8
VulDB Temp Score: 8.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Remote Code Execution
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

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

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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-2026-36603 (🔒)
GCVE (CVE): GCVE-0-2026-36603
GCVE (VulDB): GCVE-100-368192

Entryinfo

Created: 06/03/2026 21:40
Changes: 06/03/2026 21:40 (51)
Complete: 🔍
Cache ID: 216::103

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