RCE in Openremote
CVE-2026-39842
OpenRemote is an open-source IoT platform. Versions 1.21.0 and below contain two interrelated expression injection vulnerabilities in the rules engine that allow arbitrary code execution on the server. The JavaScript rules engine executes user-supplied scripts via Nashorn's ScriptEngine.eval() without sandboxing, class filtering, or access restrictions, and the authorization check in RulesResourceImpl only restricts Groovy rules to superusers while leaving JavaScript rules unrestricted for any user with the write:rules role. Additionally, the Groovy rules engine has a GroovyDenyAllFilter security filter that is defined but never registered, as the registration code is commented out, rendering the SandboxTransformer ineffective for superuser-created Groovy rules. A non-superuser attacker with the write:rules role can create JavaScript rulesets that execute with full JVM access, enabling remote code execution as root, arbitrary file read, environment variable theft including database credentials, and complete multi-tenant isolation bypass to access data across all realms. This issue has been fixed in version 1.22.0.
Vulnerability class: RCE (Remote Code Execution)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.009 (58.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: -0.000
Affected products
- Openremote — versions < 1.22.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/openremote/openremote/security/advisories/GHSA-7mqr-33rv-p3mp (Exploit, Vendor Advisory)
- github.com/openremote/openremote/releases/tag/1.22.0 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-39842?
- CVE-2026-39842 is a critical-severity vulnerability in Openremote, classified under Code Injection. CVSS score: 9.9/10. Published 2026-04-15.
- How severe is CVE-2026-39842?
- Critical severity. CVSS v3 base score is 9.9 out of 10.
- Is CVE-2026-39842 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.