CVE-2026-82180
Received Received - Intake

Authentication Bypass via X.509 Certificate in Eclipse Arrowhead

Publication date: 2026-09-03

Last updated on: 2026-09-03

Assigner: Eclipse Foundation

Description
In Eclipse Arrowhead versions from 5.0.0 to 5.2.1 when the MQTT API is enabled with the certificate authentication policy, CertificateMqttFilter parses an X.509 certificate that the client sends inside the MQTT message payload (the authentication field of MqttRequestTemplate) and treats its Subject DN as the authenticated identity. The certificate is decoded with CertificateFactory.generateCertificate() but its signature is never verified and its issuer chain is never validated against any trust store. Authorisation is reduced to two string comparisons on attacker-supplied data: the DN-qualifier must equal "sy" or "op", and the cloud-name part of the CN must match the server's. Both values are public (the cloud name is in the server's own TLS certificate). An attacker who can publish to the MQTT broker can therefore mint a self-signed certificate with CN=Sysop.<cloud>.<org>.arrowhead.eu, dnQualifier=op, send it as the authentication field, and be authenticated as the cloud's system operator with isSysOp == true. This passes the downstream ManagementServiceMqttFilter (request.isSysOp() → allowed) and gives full management access over MQTT. The HTTP CertificateFilter is not affected — it reads the certificate from jakarta.servlet.request.X509Certificate, which Tomcat populates only after a successful mTLS handshake against the configured trust store.

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Meta Information

Published
2026-09-03
Last Modified
2026-09-03
Generated
2026-09-03
AI Q&A
2026-09-03
EPSS Evaluated
N/A
NVD
CVE-2026-82180
EUVD
EUVD-2026-70467

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
eclipse arrowhead From 5.0.0 (inc) to 5.2.1 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-290 This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
CWE-295 The product does not validate, or incorrectly validates, a certificate.

Attack-Flow Graph

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Executive Summary

This vulnerability affects Eclipse Arrowhead versions 5.0.0 to 5.2.1 when the MQTT API with certificate authentication is enabled. The CertificateMqttFilter component parses an X.509 certificate sent in the MQTT message payload but fails to verify its signature or validate the issuer chain against a trust store. Authorization relies on weak string comparisons of attacker-controlled data, allowing an attacker to bypass authentication by sending a self-signed certificate with specific fields.

Detection Guidance

Check if Eclipse Arrowhead versions 5.0.0 to 5.2.1 are running with MQTT API enabled and certificate authentication policy. Inspect MQTT broker logs for unusual certificate payloads in authentication fields. Verify if any client can publish to the MQTT broker without proper certificate validation.

Impact Analysis

An attacker who can publish to the MQTT broker can impersonate a system operator or administrator, gaining full management access. This includes registering or deleting systems, services, devices, and manipulating authorization rules. The attack requires only the ability to publish to the MQTT broker, not access to credentials or the server itself.

Mitigation Strategies

Disable the MQTT API if not required. Upgrade to a patched version if available. Ensure MQTT brokers enforce certificate validation against a trusted store. Restrict MQTT publish permissions to authorized clients only.

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