CVE-2026-42084: OPENC3 Cosmos

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to versions 6.10.5 and 7.0.0-rc3, the OpenC3 password change functionality allows a user to change their password without providing the old password, by accepting a valid session token instead. In assumed breach scenarios, this behaviour can be exploited by an attacker who has already obtained a valid session token, to gain persistence in hijacked account (including admin) and prevent legitimate users from accessing the account. This issue has been patched in versions 6.10.5 and 7.0.0-rc3.

Affected products

• OPENC3 Cosmos: before 6.10.5 (fixed in 6.10.5); version 7.0.0 only

Published 2026-05-04. Last modified 2026-06-17.