CVE-2026-42084

CVE-2026-42084 is a high-severity vulnerability in Openc3 Cosmos with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-620.

Key facts

Description

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.

Frequently asked questions

What is CVE-2026-42084?
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.
How severe is CVE-2026-42084?
CVE-2026-42084 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-42084 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42084?
CVE-2026-42084 primarily affects Openc3 Cosmos. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42084?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42084 have an EU (EUVD) identifier?
Yes. CVE-2026-42084 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27057.
When was CVE-2026-42084 published?
CVE-2026-42084 was published on 2026-05-04 and last updated on 2026-06-17.

References

Affected products (3)

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