CVE-2026-34083

MEDIUM 6.1

signalk-server: OAuth Authorization Code Theft via Unvalidated Host Header in OIDC Flow

CVSS Score

6.1

EPSS Score

0.0%

EPSS Percentile

0th

Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.24.0, SignalK Server contains a code-level vulnerability in its OIDC login and logout handlers where the unvalidated HTTP Host header is used to construct the OAuth2 redirect_uri. Because the redirectUri configuration is silently unset by default, an attacker can spoof the Host header to steal OAuth authorization codes and hijack user sessions in realistic deployments as The OIDC provider will then send the authorization code to whatever domain was injected. This issue has been patched in version 2.24.0.

CWE	CWE-346 CWE-601
Vendor	signalk
Product	signalk-server
Published	Apr 2, 2026
Last Updated	Apr 2, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

SignalK / signalk-server

< 2.24.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/SignalK/signalk-server/security/advisories/GHSA-cxj8-ggf2-p57c github.com: https://github.com/SignalK/signalk-server/releases/tag/v2.24.0