Vulnerability · Published Apr 2, 2026 · Assigned by GitHub_M

CVE-2026-34083signalk-server: OAuth Authorization Code Theft via Unvalidated Host Header in OIDC Flow

Medium 6.1

In plain English

A medium-severity open redirect in signalk-server from SignalK. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.1%top 98.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	signalk-server	2.24.0	GHSA-cxj8-ggf2-p57c

Affected products (as reported)

Vendor	Product	Versions
SignalK	signalk-server	< 2.24.0

Weakness: CWE-346, CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

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