Cyber Resilience

CVE-2026-33950

Auth Bypass in Signalk Signal K Server ≤ 2.24.0

Published
02 April 2026
Modified
24 July 2026
Patch / advisory
CVSS Score v3.1 9.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS Score 0.0042 35th percentile
Risk Priority 68 floored blend · peak EPSS

Summary

CVE-2026-33950 is a critical-severity Improper Authorization (CWE-285) vulnerability in Signalk Signal K Server. Its CVSS base score is 9.4 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 35th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-33950 is a privilege escalation vulnerability in Signal K Server, an application that runs on a central hub in boats to manage vessel data. Prior to version 2.24.0-beta.4, the flaw allows Admin Role Injection via the /enableSecurity endpoint, enabling attackers to bypass authentication and authorization controls. It is associated with CWE-285 (Improper Authorization), CWE-288 (Authentication Bypass Using an Alternate Path or Channel), and CWE-862 (Missing Authorization), and carries a CVSS v3.1 base score of 9.4 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L), reflecting high confidentiality, integrity, and limited availability impact.

An unauthenticated remote attacker can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation grants full Administrator access to the Signal K Server at any time, allowing the attacker to modify sensitive vessel routing data, alter server configurations, and access restricted endpoints, potentially compromising navigation safety and operational integrity.

The issue has been addressed in Signal K Server version 2.24.0-beta.4. Security practitioners should upgrade to this version or later. Additional details are available in the GitHub security advisory at https://github.com/SignalK/signalk-server/security/advisories/GHSA-x8hc-fqv3-7gwf and the release notes at https://github.com/SignalK/signalk-server/releases/tag/v2.24.0-beta.4.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1548.001 Setuid and Setgid Privilege Escalation
An adversary may abuse configurations where an application has the setuid or setgid bits set in order to get code running in a different (and possibly more privileged) user’s context.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-1167Shared CWE-285, CWE-862
CVE-2025-1361Shared CWE-285, CWE-862
CVE-2024-5053Shared CWE-285, CWE-862
CVE-2025-54378Shared CWE-285, CWE-862
CVE-2024-10598Shared CWE-285, CWE-862
CVE-2023-6496Shared CWE-285, CWE-862
CVE-2024-9531Shared CWE-285, CWE-862
CVE-2025-29926Shared CWE-285, CWE-862
CVE-2023-6731Shared CWE-285, CWE-862
CVE-2024-6375Shared CWE-285, CWE-862

Affected Assets

signalk
signal k server
2.24.0 · ≤ 2.24.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 18 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V6.6.1
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

Mandates that access-control decisions are made and applied to each request before access occurs.

Requires a tamperproof, always-invoked reference monitor that performs authorization checks.

Directly requires enforcement of approved authorizations for every access request, stopping improper or missing checks.

Limits granted privileges so that even a bypassed check affects fewer resources.

Mandates unique identification and authentication for all organizational users, covering the primary authentication requirement.

Controls all external and key internal interfaces, reducing the chance of unauthenticated alternate channels.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Requiring authentication on every channel and path directly eliminates alternate-path bypasses.

PR.AA-05 full match
prevents

Explicitly requires defining, enforcing, and reviewing authorizations and least privilege, directly preventing missing authorization checks.

PR.IR-01 mostly match
prevents

Protecting networks and environments from unauthorized logical access blocks bypass via undocumented channels.

PR.PS-06 mostly match
prevents

Secure SDLC practices catch and eliminate most authorization defects before release, yet a single broad outcome cannot address every design, role, and runtime facet of CWE-285.

PR.AA-01 partial match
prevents

PR.AA-01 supplies managed identities and access-request workflows that can support downstream authorization decisions, yet does nothing to enforce or verify authorization checks inside a product, leaving CWE-285 fully unaddressed by this control alone.

PR.PS-05 none match
prevents

PR.PS-05 blocks unauthorized binaries/DNS while CWE-285 is an in-product authorization-check defect, so the control neither prevents the weakness nor removes any of its risk.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect alternate-path bypasses but does not prevent them in production.

prevents

Granular, policy-driven assignment of permissions and dynamic enforcement of those permissions prevent the incorrect or missing authorization decisions that lead to improper authorization flaws.

degrades

Secure authentication control directly mitigates bypass by requiring strong, consistent authentication on all paths.

prevents

By requiring documented authorization rules and periodic policy reviews, the control makes it less likely that authorization decisions will be omitted or implemented inconsistently across applications.

prevents

Mapping access rights to information classification and business requirements forces correct enforcement of authorization decisions, blocking the incorrect authorization weakness at the policy and implementation stage.

degrades

Authentication information management ensures credentials and mechanisms are consistently applied across all access paths.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (4 rules)
  • V-248598 There must be no ".shosts" files on the OL 8 operating system. prevents CWE-288
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-288
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285, CWE-862
Oracle Linux 9 (2 rules)
  • V-271757 OL 9 file systems must not contain shosts.equiv files. prevents CWE-288
  • V-271758 OL 9 file systems must not contain .shosts files. prevents CWE-288
RHEL 7 (6 rules)
  • V-204440 Red Hat Enterprise Linux operating systems version 7.2 or newer using Unified Extensible Firmware Interface (UEFI) must require authentication upon booting into single-user and maintenance modes. prevents CWE-288
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-288
  • V-251704 The Red Hat Enterprise Linux operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285, CWE-862
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-285

References