Auth bypass in Sungrow Isolarcloud

CVE-2025-29756

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.

Vulnerability class: Broken Access Control

Published · last modified .

EPSS exploit prediction

EPSS: 0.003 (15.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-29756: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Weakness classification (CWE)

References