iSteamX application: Improper Isolation or Compartmentalization
CVE-2026-95699 is a critical-severity improper isolation or compartmentalization vulnerability in iSteamX application from MrSteam, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected iSteamX application versions: v1.3.42 (build 44). The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of iSteamX application you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MrSteam | iSteamX application | v1.3.42 (build 44) | Not stated |
| MrSteam | iSteamX Hub | v4.2.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H. Scored by CNA (hq.dhs.gov).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.4 | High | CNA (hq.dhs.gov) |
| CVSS 3.1 | 9.6 | Critical | CNA (hq.dhs.gov) |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Isolation or Compartmentalization
The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.
How developers prevent this class of flaw
- Break up privileges between different modules, objects, or entities. Minimize the interfaces between modules and require strong access control between them.
More Improper Isolation or Compartmentalization vulnerabilities (CWE-653)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Isolation or Compartmentalization vulnerabilities
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- 9.8 Critical severity
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- 9.8 Critical severity
- 8.5 High severity
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