CVE-2026-42084: OpenC3 COSMOS: Hijacked session token can be used to reset password for persistence

Published May 4, 2026
·
Updated

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 Software

4 affected components
OpenC3 OpenC3 COSMOS<6.10.5, <7.0.0-rc3
OpenC3 COSMOS<6.10.5
OpenC3 COSMOS=7.0.0-rc1
OpenC3 COSMOS=7.0.0-rc2

Event History

May 4, 2026
CVE Published
via MITRE·05:11 PM
Data Sourced
via MITRE·05:11 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-42084?

The severity of CVE-2026-42084 is considered high due to the potential for unauthorized password resets via hijacked session tokens.

2

How do I fix CVE-2026-42084?

To fix CVE-2026-42084, upgrade OpenC3 COSMOS to versions 6.10.5 or later, or 7.0.0-rc3 or later.

3

What versions of OpenC3 COSMOS are affected by CVE-2026-42084?

CVE-2026-42084 affects OpenC3 COSMOS versions prior to 6.10.5 and 7.0.0-rc3.

4

What type of vulnerability is CVE-2026-42084?

CVE-2026-42084 is a session hijacking vulnerability that allows attackers to reset user passwords.

5

Who is impacted by CVE-2026-42084?

Users of OpenC3 COSMOS prior to the fixed versions are impacted by CVE-2026-42084.

Contact

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