EUVD-2026-18376
GHSA-cxj8-ggf2-p57c
Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Lifecycle Timeline
4DescriptionGitHub Advisory
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.
AnalysisAI
SignalK Server versions prior to 2.24.0 allow unauthenticated attackers to hijack OAuth2 sessions and steal authorization codes by spoofing the HTTP Host header in OIDC login and logout handlers. The vulnerability exploits the default-unset redirectUri configuration, causing the OIDC provider to send authorization codes to an attacker-controlled domain. EPSS score of 6.1 reflects moderate real-world risk despite the requirement for user interaction (UI:R) to initiate login.
Technical ContextAI
SignalK Server implements OpenID Connect (OIDC) authentication to delegate user login to an external OAuth2 provider. The vulnerability stems from CWE-346 (Origin Validation Error), where the application constructs the redirect_uri parameter for the OAuth2 authorization request by reading the unvalidated HTTP Host header rather than using a hardcoded or configuration-controlled value. When redirectUri is not explicitly configured (the default state), an attacker can inject a malicious Host header (e.g., 'attacker.com') into the login request, causing SignalK Server to instruct the OIDC provider to send the authorization code to the attacker's domain instead of the legitimate server. This is a host spoofing vulnerability that bypasses OAuth2 security assumptions that the redirect_uri matches the registered application domain.
RemediationAI
Upgrade SignalK Server to version 2.24.0 or later, which patches the Host header validation in OIDC handlers. The patch ensures that the redirect_uri is either explicitly configured by administrators or derived from a trusted source, not the unvalidated Host header. During deployment, explicitly configure the redirectUri in the OIDC settings to match the canonical domain of your SignalK Server instance; do not rely on default behavior. For users unable to upgrade immediately, restrict network access to the SignalK login endpoints via a reverse proxy or firewall, and implement strict Host header validation at the HTTP layer to reject requests with unexpected Host values. See the release notes at https://github.com/SignalK/signalk-server/releases/tag/v2.24.0 for additional configuration guidance.
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Same weakness CWE-346 – Origin Validation Error
View allSame technique Code Injection
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External POC / Exploit Code
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