CVE-2026-42086
OpenC3 COSMOS: Self-XSS in the Command Sender
Description
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 the browser when sending a command. This creates a self-XSS risk because an attacker can trigger their own script execution in the victim’s session, if allowed to influence the array parameter input, for example via phishing. If successful, an attacker may read or modify data in the authenticated browser context, including session tokens in local storage. This issue has been patched in version 7.0.0.
INFO
Published Date :
May 4, 2026, 6:16 p.m.
Last Modified :
May 8, 2026, 7:54 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update OpenC3 COSMOS to version 7.0.0 or later.
- Avoid influencing array parameter input.
- Sanitize user-supplied command parameters.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42086.
| URL | Resource |
|---|---|
| https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x | Exploit Vendor Advisory |
| https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42086 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42086
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42086 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42086 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 08, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:openc3:cosmos:*:*:*:*:open_source:*:*:* versions up to (excluding) 7.0.0 *cpe:2.3:a:openc3:cosmos:7.0.0:rc1:*:*:open_source:*:*:* *cpe:2.3:a:openc3:cosmos:7.0.0:rc2:*:*:open_source:*:*:* *cpe:2.3:a:openc3:cosmos:7.0.0:rc3:*:*:open_source:*:*:* Added Reference Type CISA-ADP: https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 04, 2026
Action Type Old Value New Value Added Reference https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x -
New CVE Received by [email protected]
May. 04, 2026
Action Type Old Value New Value Added Description 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 the browser when sending a command. This creates a self-XSS risk because an attacker can trigger their own script execution in the victim’s session, if allowed to influence the array parameter input, for example via phishing. If successful, an attacker may read or modify data in the authenticated browser context, including session tokens in local storage. This issue has been patched in version 7.0.0. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N Added CWE CWE-79 Added Reference https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x