CVE-2026-42086
Self-XSS in OpenC3 COSMOS Command Sender UI
Publication date: 2026-05-04
Last updated on: 2026-05-04
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| openc3 | cosmos | to 7.0.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows an attacker to execute scripts in the victim's browser session, potentially reading or modifying data including session tokens stored locally. This could lead to unauthorized access to sensitive information.
Such unauthorized access and potential data exposure may impact compliance with standards and regulations like GDPR and HIPAA, which require protection of personal and sensitive data against unauthorized access.
However, the provided information does not explicitly discuss the direct impact on compliance with these standards.
Can you explain this vulnerability to me?
This vulnerability exists in OpenC3 COSMOS versions prior to 7.0.0, where the Command Sender UI uses an unsafe eval() function on array-like command parameters. This allows a user-supplied payload to execute in the browser when sending a command, creating a self-XSS (Cross-Site Scripting) risk. An attacker can trigger their own script execution in the victim’s browser session if they can influence the array parameter input, for example through phishing.
If exploited, the attacker may read or modify data within the authenticated browser context, including sensitive information such as session tokens stored in local storage. This vulnerability was fixed in version 7.0.0.
How can this vulnerability impact me? :
If this vulnerability is exploited, an attacker can execute malicious scripts in your browser session, potentially allowing them to read or modify sensitive data such as session tokens stored locally. This can lead to unauthorized access to your account or data within the application.
The attack requires the attacker to influence the array parameter input, which could be done via phishing or other social engineering techniques. The impact includes loss of confidentiality and integrity of data within the authenticated session.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade OpenC3 COSMOS to version 7.0.0 or later, where the unsafe eval() usage has been patched.
Additionally, be cautious of phishing attempts that could allow attackers to influence array parameter inputs and trigger self-XSS.