GitHub Advisoryadvisory · RubyGems, PyPI

GHSA-ffq5-qpvf-xq7x OpenC3 COSMOS is Vulnerable to Self-XSS Through the Command Sender

MEDIUM Published 2026-04-22 Modified 2026-05-29 Official page ↗
Aliases
CVE-2026-42086
Ecosystem
RubyGems, PyPI
Packages
openc3
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Weaknesses
CWE-79
Reviewed
2026-04-22

Affected packages

• RubyGems openc3: < 7.0.0 → fixed in 7.0.0 • PyPI openc3: < 7.0.0 → fixed in 7.0.0

Description

Summary 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. Details The unsafe `eval()` usage on user-supplied ARRAY parameters happens in `convertToValue` method in CommandSender.vue PoC 1. Using a drop-down form, choose any command that supports ARRAY parameters, 2. Inside square brackets “[…]” place a JavaScript code to be executed 3. Send command to CmdTlmServer using dedicated “Send” button 4. Observe JavaScript code being executed in the current browser session context Below example uses `INST ARYCMD` to execute simple JavaScript code snippet `alert(“XSS”)`. Impact Local JavaScript execution in the user's browser

Related

Alias · CVE (1)

  • CVE-2026-42086 OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. vulnerability

Weakness · CWE (1)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References