Medium severity · published Apr 2, 2026
CVE-2026-34083
signalk-server: OAuth Authorization Code Theft via Unvalidated Host Header in OIDC Flow
6.1
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
signalk-server · SignalK
< 2.24.0 · source: vendor
SK
Signal K Server · Signalk
before 2.24.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34083
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34083
Product
https://github.com/SignalK/signalk-server/releases/tag/v2.24.0
Exploit
https://github.com/SignalK/signalk-server/security/advisories/GHSA-cxj8-ggf2-p57c
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