CVE-2026-55591

Published Sep 15, 2026

Last updated 8 hours ago

CVSS medium 5.8
Port (80)

Overview

Description
Signal K Server is a server application that runs on a central hub in a boat. Prior to 2.28.0, makeRemoteRequest() in src/serverroutes.ts accepted attacker-controlled host, port, useTLS, and selfsignedcert parameters from the testSignalKConnection, requestAccess, and checkAccessRequest endpoints without validating the destination. When security was not configured, addAdminMiddleware() was a no-op in dummysecurity.ts, leaving all three endpoints accessible without authentication. The server could be forced to contact loopback, private, link-local, cloud metadata, or arbitrary external destinations, and selfsignedcert could disable certificate verification for outbound HTTPS requests. The checkAccessRequest endpoint also interpolated requestId into its destination path, allowing traversal to other paths on the selected host. Distinct success, connection-refused, and timeout responses enabled internal port scanning; returned response bodies enabled cloud metadata and internal-service data exfiltration; requestAccess enabled server-side POST requests with attacker-controlled JSON; and access to cluster-internal services could support lateral movement. This issue is fixed in version 2.28.0.
Source
security-advisories@github.com
NVD status
Deferred

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.8
Impact score
1.4
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Severity
MEDIUM

Weaknesses

security-advisories@github.com
CWE-918

Social media

Hype score
Not currently trending

Related CVEs

  1. 9Router is an AI router & token saver. In 0.5.4 and earlier, the POST /api/auth/oidc/test endpoint in src/app/api/auth/oidc/test/route.js passes the user-controlled issuerUrl parameter to fetchOidcDiscovery() in src/lib/auth/oidc.js without restricting private or loopback destinations, allowing unauthenticated attackers when dashboard login is disabled to scan internal services and reflect OIDC discovery fields including token_endpoint and jwks_uri.•CVE-2026-56677
  2. Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability •CVE-2026-56155
  3. Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability•CVE-2026-56164
  4. ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.2.6, 5.3.5, 5.4.4, 5.5.4, and 6.0, a NULL-pointer dereference exists in the WebSocket subprotocol-negotiation path of the esp_http_server component. While parsing the client-supplied Sec-WebSocket-Protocol request header during the WebSocket handshake, the tokenisation result is dereferenced without a NULL check, so a malformed header value can crash the server before any application-level authentication runs. This issue has been patched in versions 5.2.7, 5.3.6, 5.4.5, 5.5.5, and 6.0.1.•CVE-2026-45541
  5. A vulnerability in the access validation of internal REST APIs of Cisco Secure Workload could allow an unauthenticated, remote attacker to access site resources with the privileges of the Site Admin role. This vulnerability is due to insufficient validation and authentication when accessing REST API endpoints. An attacker could exploit this vulnerability if they are able to send a crafted API request to an affected endpoint. A successful exploit could allow the attacker to read sensitive information and make configuration changes across tenant boundaries with the privileges of the Site Admin user. •CVE-2026-20223

References

Sources include official advisories and independent security research.