CVE-2026-42088

CVE-2026-42088 is a critical-severity vulnerability in Openc3 Cosmos with a CVSS 3.x base score of 9.6. 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-250.

Key facts

Description

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-rc3, the Script Runner widget allows users to execute Python and Ruby scripts directly from the openc3-COSMOS-script-runner-api container. Because all the docker containers share a network, users can execute specially crafted scripts to bypass the API permissions check and perform administrative actions, including reading and modifying data inside the Redis database, which can be used to read secrets and change COSMOS settings, as well as read and write to the buckets service, which holds configuration, log, and plugin files. These actions are normally only available from the Admin Console or with administrative privileges. Any user with permission to create and run scripts can connect to any service in the docker network. This issue has been patched in version 7.0.0-rc3.

Frequently asked questions

What is CVE-2026-42088?
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-rc3, the Script Runner widget allows users to execute Python and Ruby scripts directly from the openc3-COSMOS-script-runner-api container. Because all the docker containers share a network, users can execute specially crafted scripts to bypass the API permissions check and perform administrative actions, including reading and modifying data inside the Redis database, which can be used to read secrets and change COSMOS settings, as well as read and write to the buckets service, which holds configuration, log, and plugin files. These actions are normally only available from the Admin Console or with administrative privileges. Any user with permission to create and run scripts can connect to any service in the docker network. This issue has been patched in version 7.0.0-rc3.
How severe is CVE-2026-42088?
CVE-2026-42088 has a CVSS 3.x base score of 9.6, rated critical 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-2026-42088 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42088?
CVE-2026-42088 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-2026-42088?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-42088 have an EU (EUVD) identifier?
Yes. CVE-2026-42088 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27065.
When was CVE-2026-42088 published?
CVE-2026-42088 was published on 2026-05-04 and last updated on 2026-06-17.

References

Affected products (3)

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