# 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.

Source: https://junglewise.ai/threats/cve-2026-42084-openc3-cosmos-unverified-password-change-via-session-token  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-04. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

CVE-2026-42084 · Severity: high · CVSS 8.1 · Published 2026-05-04

OpenC3 COSMOS, a platform for command and control of spacecraft and other systems, contains a flaw in how it handles password changes. An attacker who has managed to steal a user's active session token can use that token to permanently change the account's password without knowing the original one. This allows the attacker to lock out legitimate users and maintain long-term control over the system, potentially including administrative accounts.

Technologies: [Openc3 Cosmos](https://junglewise.ai/threats/technologies/cosmos), [openc3 (PyPI)](https://junglewise.ai/threats/technologies/pypi-openc3), [openc3 (RubyGems)](https://junglewise.ai/threats/technologies/openc3). Vendors: [Openc3](https://junglewise.ai/threats/vendors/openc3), [PyPI](https://junglewise.ai/threats/vendors/pypi), [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2026-42084 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42084 being exploited in the wild.

**How severe is CVE-2026-42084?** High severity, with a CVSS score of 8.1, published 4 May 2026.

**Which products and versions are affected?** Openc3 Cosmos < 6.10.5, >= 7.0.0.pre.rc1, < 7.0.0-rc3; openc3 (PyPI) ECOSYSTEM:introduced=0,fixed=6.10.5; openc3 (RubyGems) ECOSYSTEM:introduced=0,fixed=6.10.5.

**Is there a fix for CVE-2026-42084?** Yes. openc3 (PyPI): upgrade to 6.10.5 or later; openc3 (RubyGems): upgrade to 6.10.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42084 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-42084?** Check whether you run Openc3 Cosmos, openc3 (PyPI) or openc3 (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- openc3 (PyPI): upgrade to 6.10.5 or later

  ```sh
  pip install "openc3>=6.10.5"
  ```

- openc3 (RubyGems): upgrade to 6.10.5 or later

  ```sh
  bundle update openc3
  ```


## Technical details

A design flaw in the OpenC3 COSMOS authentication model (specifically within authentication.rb) allows session tokens and passwords to be used interchangeably for identity verification during password reset operations. Because session tokens are not invalidated upon a password change, an attacker with a hijacked token can submit a password change request by providing the token in place of the 'old_password' field. This enables the attacker to maintain persistence even after a legitimate user attempts to secure the account by changing their password. The vulnerability is tracked as CWE-620 (Unverified Password Change) and is resolved in versions 6.10.5 and 7.0.0-rc3.

## Affected products

- OpenC3 COSMOS < 6.10.5, >= 7.0.0.pre.rc1, < 7.0.0-rc3

## Identifiers

- CVE-2026-42084
- GHSA-wgx6-g857-jjf7
- PYSEC-2026-2242

## Timeline

- 2026-04-20: disclosed: Initial disclosure to OpenC3/cosmos repository
- 2026-04-22: advisory: GitHub Advisory published
- 2026-05-04: other: NVD publication date

## References

- [https://api.github.com/users/ctrlsill](https://api.github.com/users/ctrlsill)
- [https://github.com/ctrlsill](https://github.com/ctrlsill)
- [https://api.github.com/users/ctrlsill/gists%7B/gist_id%7D](https://api.github.com/users/ctrlsill/gists%7B/gist_id%7D)
- [https://api.github.com/users/ctrlsill/repos](https://api.github.com/users/ctrlsill/repos)
- [https://avatars.githubusercontent.com/u/86782008?v=4](https://avatars.githubusercontent.com/u/86782008?v=4)
- [https://api.github.com/users/ctrlsill/events%7B/privacy%7D](https://api.github.com/users/ctrlsill/events%7B/privacy%7D)

## Related threats

- [OpenC3 COSMOS authenticated remote code execution via config overlay](https://junglewise.ai/threats/cve-2026-77602-openc3-cosmos-authenticated-remote-code-execution-via-config)
- [OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.12.0 until 7.](https://junglewise.ai/threats/cve-2026-77601-openc3-cosmos-authenticated-os-command-injection-via-pypi-url)
- [OpenC3 COSMOS stored cross-user XSS in BUTTON widget](https://junglewise.ai/threats/cve-2026-77394-openc3-cosmos-stored-cross-user-xss-in-button-widget)
- [OpenC3 COSMOS privilege escalation via Script Runner API bypass](https://junglewise.ai/threats/cve-2026-42088-openc3-cosmos-privilege-escalation-via-script-runner-api-bypass)
- [OpenC3 COSMOS SQL injection in QuestDB Time-Series Database](https://junglewise.ai/threats/cve-2026-42087-openc3-cosmos-sql-injection-in-questdb-time-series-database)