CVE-2025-68271: openc3-api Vulnerable to Unauthenticated Remote Code Execution

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.6%, percentile 50: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 50% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes openc3 (RubyGems) >= 5.0.6, < 6.10.2, fixed in 6.10.2. Check your lockfile, including transitive dependencies.

What it is

OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.0.0 to 6.10.1, OpenC3 COSMOS contains a critical remote code execution vulnerability reachable through the JSON-RPC API. When a JSON-RPC request uses the string form of certain APIs, attacker-controlled parameter text is parsed into values using String#converttovalue. For array-like inputs, converttovalue executes eval(). Because the cmd code path parses the command string before calling authorize(), an unauthenticated attacker can trigger Ruby code execution even though the request ultimately fails authorization (401). This vulnerability is fixed in 6.10.2.

From the GitHub advisory

Summary OpenC3 COSMOS contains a critical remote code execution vulnerability reachable through the JSON-RPC API. When a JSON-RPC request uses the string form of certain APIs, attacker-controlled parameter text is parsed into values using String#converttovalue. For array-like inputs, converttovalue executes eval().

Because the cmd code path parses the command string before calling authorize(), an unauthenticated attacker can trigger Ruby code execution even though the request ultimately fails authorization (401).

Weakness type: CWE-95.

Product: openc3 (RubyGems) · Assigned by: GitHub_M · Published: 2026-01-13

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.64% probability of exploitation activity in the next 30 days; percentile 50.

Timeline

• 2026-01-13 — CVE record last updated
• 2026-01-13 — CVE record published by GitHub_M
• 2026-01-13 — GitHub-reviewed advisory GHSA-w757-4qv9-mghp published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-w757-4qv9-mghp github.com
2. CVE.org record CVE-2025-68271 cve.org
3. NVD entry CVE-2025-68271 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical RubyGems advisories · Today’s Security Digest