CVE-2026-34083

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

MEDIUM
6.1
CVSS Score
Published: April 2, 2026 at 04:14 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
1 product affected across 1 vendorSignal K Server

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.1%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.24.0
Affected range stops below 2.24.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/SignalK/signalk-server/security/advisories/GHSA-cxj8-ggf2-p57c
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/SignalK/signalk-server/releases/tag/v2.24.0

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-346CWE-601

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