CVE-2026-39842 Security Alert: CRITICAL Vulnerability

Urgent: CVE-2026-39842 requires immediate attention.

· 3 min read

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Executive Summary

A critical vulnerability (CVE-2026-39842) has been discovered in the OpenRemote IoT platform's rules engine, allowing attackers to execute arbitrary code on servers. This vulnerability is particularly dangerous as it affects non-superuser roles that can create JavaScript rules without restrictions. Immediate action is required to mitigate the risk of remote code execution (RCE) and ensure the security of your applications.

Immediate Action

  • Upgrade to the latest version of io.openremote:openremote-manager as soon as possible.
  • If an upgrade is not feasible, disable JavaScript rule creation for non-superusers until a patch is available.
  • Review user roles and permissions to limit access to sensitive functionalities.
  • Monitor server logs for unusual activity that may indicate exploitation attempts.
  • Consult the vendor's security advisory for further guidance (link to be added).

Affected Versions

  • io.openremote:openremote-manager@<=1.20.2 vulnerable; upgrade to 1.20.3+

Resolution Guide

To upgrade the affected package, execute the following command:

mvn dependency:upgrade -DgroupId=io.openremote -DartifactId=openremote-manager -Dversion=1.20.3

For Docker users, update your docker-compose.yml to pull the latest image:

docker pull openremote/manager:latest

To prevent exploitation, consider implementing the following configuration changes:

 
# Disable JavaScript rule creation for non-superusers
# Modify your security settings or user role definitions accordingly.

Example of a minimal code fix (if applicable):


// Ensure JavaScript rules are checked for superuser privileges
if (ruleset.getLang() == Ruleset.Lang.JAVASCRIPT && !isSuperUser()) {
    throw new ForbiddenException("Forbidden");
}

Detection & Verification

To check if your current version is vulnerable, run:

mvn dependency:tree | grep openremote-manager

Verify the fix by checking the version after the upgrade:

mvn dependency:tree | grep openremote-manager

Risk and Impact

This vulnerability allows attackers to execute arbitrary code on the server, potentially leading to full server compromise. The blast radius includes any application relying on the affected version of OpenRemote, exposing sensitive data and system integrity.

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