CVE-2026-42086 — Cross-Site Scripting (XSS)
CVE-2026-42086 — OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to version 7.0.0, the Command Sender UI uses an unsafe eval() function on array-like command parameters, which allows a user-supplied payload to execute in t
What This Means For You
- If your environment is affected by CWE-79, review your exposure and prioritize patching based on your environment. Monitor vendor advisories for CVE-2026-42086 updates and patches.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42086 - OpenC3 COSMOS Command Sender XSS via unsafe eval
title: CVE-2026-42086 - OpenC3 COSMOS Command Sender XSS via unsafe eval
id: scw-2026-05-04-ai-1
status: experimental
level: medium
description: |
Detects potential exploitation of CVE-2026-42086 by looking for requests to the OpenC3 COSMOS Command Sender UI that contain JavaScript eval() or new Function() calls within the query parameters. This indicates an attempt to inject and execute arbitrary JavaScript in the browser via the unsafe eval() function used for array-like command parameters.
author: SCW Feed Engine (AI-generated)
date: 2026-05-04
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42086/
tags:
- attack.initial_access
- attack.t1189
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/cosmos/command_sender'
cs-uri-query|contains:
- 'eval('
- 'new Function('
condition: cs-uri AND cs-uri-query
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42086 | vulnerability | CVE-2026-42086 |
| CWE-79 | weakness | CWE-79 |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 04, 2026 at 21:16 UTC |
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