CVE-2026-95699: MrSteam iSteamX Improper Isolation or Compartmentalization

Severity: critical (CVSS 9.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-24 · updated 2026-09-25
Weakness: CWE-653

Description

Prior to 9/18/2026, the iSteamX mobile application's AWS policy could grant authenticated users access to wildcard MQTT topics, which can expose other users' device data and allow the attacker to start and stop other connected users' devices. This risked exposing user profile information and potential scalding due to unintended device activation.

Affected products

MrSteam iSteamX application: v1.3.42 (build 44)
MrSteam iSteamX Hub: v4.2.1

References

https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/VA/white/2026/va-26-267-01.json
https://www.mrsteam.com/contactus/

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