CVE-2026-33950: Signal K Server: Privilege Escalation by Admin Role Injection via /enableSecurity

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.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.5%, percentile 40: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 40% of all scored CVEs (low). 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 signalk-server (npm) < 2.24.0-beta.4, fixed in 2.24.0-beta.4. Check your lockfile, including transitive dependencies.

What it is

Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.24.0-beta.4, there is a privilege escalation vulnerability by Admin Role Injection via /enableSecurity. An unauthenticated attacker can gain full Administrator access to the SignalK server at any time, allowing them to modify sensitive vessel routing data, alter server configurations, and access restricted endpoints. This issue has been patched in version 2.24.0-beta.4.

From the GitHub advisory

Summary

According to SignalK's security documentation, when a server is first initialized without security enabled, the /skServer/enableSecurity endpoint is intentionally exposed to allow the owner to set up the initial admin account. This initial open access is by design.

However, the critical vulnerability is that this route is never deregistered or disabled after the initial successful setup. Even after the genuine administrator has created their account, restarted the server, and activated token security, the /skServer/enableSecurity route remains perpetually open.

Furthermore, the endpoint explicitly trusts the type field provided in the request body, passing it directly into the server's security configuration without validation. Because the route remains permanently listening, any unauthenticated user can call this endpoint at any time to silently inject a new, fully privileged admin account alongside the legitimate ones.

Vulnerable Root Cause

Weakness type: CWE-285, CWE-288, CWE-862.

Product: signalk-server (npm) · Assigned by: GitHub_M · Published: 2026-04-02

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

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 poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 40.

Timeline

• 2026-04-02 — CVE record published by GitHub_M
• 2026-04-03 — CVE record last updated
• 2026-04-03 — GitHub-reviewed advisory GHSA-x8hc-fqv3-7gwf 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-x8hc-fqv3-7gwf github.com
2. CVE.org record CVE-2026-33950 cve.org
3. NVD entry CVE-2026-33950 nvd.nist.gov

Other references from the CVE record and advisory

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

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