CVE-2025-29756 HIGH

CVE-2025-29756: MQTT implementation in Sungrow iSolarCloud allowed users to subscribe to all data of all connected inverters

Vendor Sungrow
Product iSolarCloud
Weakness CWE-862 · Missing authorization
Published June 11, 2025
Last update June 23, 2025

CVSS base score

8.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/AU:Y

What the vulnerability does

01Description

SunGrow's back end users system iSolarCloud https://isolarcloud.com  uses an MQTT service to transport data from the user's connected devices to the user's web browser.  The MQTT server however did not have sufficient restrictions in place to limit the topics that a user could subscribe to.  While the data that is transmitted through the MQTT server is encrypted and the credentials for the MQTT server are obtained though an API call, the credentials could be used to subscribe to any topic and the encryption key can be used to decrypt all messages received. An attack with an account on iSolarCloud.com could extract MQTT credentials and the decryption key from the browser and then use an external program to subscribe to the topic '#' and thus recieve all messages from all connected devices.

Key dates

02Disclosure timeline

June 11, 2025 CVE published
June 23, 2025 Record updated