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CVE-2026-42086

22
FAUCET Score

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.

First published: May 4, 2026Last modified: May 4, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 7.0.0CPE matchmatch criteria
cpe:2.3:a:openc3:cosmos:*:*:*:*:open_source:*:*:*
7.0.0CPE matchmatch criteria
cpe:2.3:a:openc3:cosmos:7.0.0:rc1:*:*:open_source:*:*:*
7.0.0CPE matchmatch criteria
cpe:2.3:a:openc3:cosmos:7.0.0:rc2:*:*:open_source:*:*:*
7.0.0CPE matchmatch criteria
cpe:2.3:a:openc3:cosmos:7.0.0:rc3:*:*:open_source:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.6MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.1
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.20%
Probability of exploitation in next 30 days
EPSS Percentile
10.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0020 is in the 10th percentile among its peer group of 15,239 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

pippatch availablevia ghsa
Product: openc3Fixed in: 7.0.0
rubygemspatch availablevia ghsa
Product: openc3Fixed in: 7.0.0
github_advisoryvendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

rubygemsGHSA-ffq5-qpvf-xq7xmedium

OpenC3 COSMOS is Vulnerable to Self-XSS Through the Command Sender

Apr 22, 2026

References

github.com / OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x
ExploitVendor Advisory