CVE-2026-34083Public exploitNetwork attack vector

OIDC code theft via unvalidated Host header

Published Apr 2, 2026 · Updated Apr 2, 2026

Open redirect in Signal K Server 2.20.0 and later before 2.24.0 allows remote attackers to steal OIDC authorization codes via a spoofed Host header. When redirectUri is unset, the OIDC login handler reads the HTTP Host header and inserts it without validation into redirect_uri passed to the provider. OIDC must be enabled and a user must complete the login flow; the provider then sends the code to the injected domain, enabling session hijacking.

CVSS severity6.1
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Signal K Server 2.20.0 and later before 2.24.0 allows remote attackers to steal OIDC authorization codes via a spoofed Host header. When redirectUri is unset, the OIDC login handler reads the HTTP Host header and inserts it without validation into redirect_uri passed to the provider. OIDC must be enabled and a user must complete the login flow; the provider then sends the code to the injected domain, enabling session hijacking.

The record

CVE
CVE-2026-34083
Published
Apr 2, 2026
Updated
Apr 2, 2026
Vendor
Signal K
Product
Signal K Server
Classifications
CWE-346, CWE-601, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.24.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Signal K · Signal K Serverversion=< 2.24.0

Published CVSS scores

6.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-346Origin Validation Error
CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1528Steal Application Access Token

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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