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Fencer Intel
critical 9.8

CVE-2026-123807 json

Signal K Server: Unauthenticated path traversal in resources-provider v2 API leads to JWT secret disclosure, admin impersonation and remote code execution

published 10d ago modified 5h ago also GHSA-4xm8-rg9h-jhq2 , EUVD-2026-120438

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

Signal K Server is a server application that runs on a central hub in a boat. From 2.0.0 until 2.34.0 for Signal K Server and from 1.0.0 until 1.5.3 for @signalk/resources-provider, the v2 REST route GET /signalk/v2/api/resources/:resourceType/:resourceId accepts an unsafe resourceId that can escape the intended resource directory. The route passes the attacker-controlled resourceId through src/api/resources/index.ts to FileStore.getResource() in packages/resources-provider-plugin/src/filestorage.ts without adequate path containment, allowing arbitrary JSON files reachable by the server to be read. Related PUT and DELETE resource operations can write or delete files outside the storage root. Deployments with allow_readonly enabled permit anonymous reads, while other deployments require a readonly user token. Reading security.json exposes the HS256 JWT signing secret and password hashes, allowing an attacker to forge an administrator token. Administrative access to POST /skServer/providers can then create an Execute provider that runs commands with the server process privileges and persists its configuration across restarts. This issue is fixed in Signal K Server 2.34.0 and @signalk/resources-provider 1.5.3.

Patch / fix

  • npm signalk-server 2.34.0
  • npm @signalk/resources-provider 1.5.3

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CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm signalk-server
>=2.0.0, <2.34.0
2.34.0
npm @signalk/resources-provider
>=1.0.0, <1.5.3
1.5.3

Affected products

  • SignalK signalk-server
  • @signalk resources-provider

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.