CVE-2026-42084

HIGH
Published May 4, 2026 Modified May 8, 2026 CWE-620

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.

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CVSS v3.1 Score

8.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0003
Probability of exploitation
0.10%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-620 CWE-620

Affected Products

Vendor Product
openc3 cosmos
openc3 cosmos
openc3 cosmos

References

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. It has a CVSS v3.1 base score of 8.1 (HIGH).
How severe is CVE-2026-42084? +
CVE-2026-42084 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0003, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-42084? +
CVE-2026-42084 affects products from openc3, specifically: cosmos. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-42084? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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