What is CVE-2026-42086?

CVE-2026-42086 is a medium-severity vulnerability in Openc3 Cosmos, classified under Cross-site Scripting. CVSS score: 4.6/10. Published 2026-05-04.

How severe is CVE-2026-42086?

Medium severity. CVSS v3 base score is 4.6 out of 10.

XSS in Openc3 Cosmos

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 al…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.000 (11.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N.

Affected products

Openc3 Cosmos — versions < 7.0.0, 7.0.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

https://github.com/OpenC3/cosmos/security/advisories/GHSA-ffq5-qpvf-xq7x (x_refsource_CONFIRM, Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42086?: CVE-2026-42086 is a medium-severity vulnerability in Openc3 Cosmos, classified under Cross-site Scripting. CVSS score: 4.6/10. Published 2026-05-04.
How severe is CVE-2026-42086?: Medium severity. CVSS v3 base score is 4.6 out of 10.