CVE-2026-39842 | OpenRemote is Vulnerable to Expression Injection

Exp

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.

Published: 2026-04-15 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-39842 is rated High Exploit Risk (74.9/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.92%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-39842

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-39842

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.06% 0.92% +0.87%
2 2026-04-21 0.16% 0.06% -0.11%
3 2026-04-20 — 0.16% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-39842

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.9 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 6.0 [email protected]

Weakness enumeration for CVE-2026-39842

GitHub Security Advisory for CVE-2026-39842

GHSA-7mqr-33rv-p3mp · Severity: critical · Ecosystem: maven — Expression Injection in OpenRemote

Affected software / configurations for CVE-2026-39842

Vendor Product Version Raw CPE
openremote openremote < 1.22.0 cpe:2.3:a:openremote:openremote:*:*:*:*:*:*:*:*

References for CVE-2026-39842

cvelogic Threat Intelligence