Eclipse Arrowhead 5.0.0-5.2.1 MQTT Cert Auth Bypass (Unverified X.509)
CVE-2026-82180 Published on September 3, 2026
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.
Vulnerability Analysis
CVE-2026-82180 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Types
Improper Certificate Validation
The software does not validate, or incorrectly validates, a certificate. When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.
Authentication Bypass by Spoofing
This attack-focused weakness is caused by improperly implemented authentication schemes that are subject to spoofing attacks.
Affected Versions
Eclipse Foundation Eclipse Arrowhead:- Version 5.0.0, <= 5.2.1 is affected.