Apache PLC4X up to 0.9.x OPC UA driver certificate validation

Summaryinfo

A vulnerability was found in Apache PLC4X up to 0.9.x. It has been rated as problematic. This impacts an unknown function of the component OPC UA driver. Performing a manipulation results in certificate validation. This vulnerability is known as CVE-2026-102508. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Apache PLC4X up to 0.9.x. This affects an unknown function of the component OPC UA driver. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. The summary by CVE is:

Improper Verification of Cryptographic Signature and Improper Certificate Validation in the OPC UA driver of Apache PLC4X (PLC4J) allows an attacker in a network position between client and server to impersonate the OPC UA server and to read, forge or modify secure-channel traffic, including user credential ssent by the client. The defect manifests differently depending on the version: - In 0.9.0 through 0.11.0 a failed message-signature check is only logged and never enforced, and there is no mechanism to verify the server certificate: it is taken from the unauthenticated GetEndpoints discovery response and used to encrypt the user's password. - In 0.12.0 through 0.13.1 the signature check is inverted (valid signatures are rejected, invalid ones accepted), and server certificates are accepted without a trust anchor by default. - In all affected versions the default security policy is None. Starting with 0.12.0 the driver additionally continues silently at a weaker security policy than the one configured, and starting with 0.13.0 endpoint selection prefers the weakest matching endpoint. Users checking only for one of these mechanisms may wrongly conclude they are unaffected. This issue affects Apache PLC4X: from 0.9.0 before 1.0.0. Users are recommended to upgrade to version 1.0.0, which fixes the issue. Version 1.0.0 verifies message signatures correctly, refuses to connect unless the server certificate can be verified against a configured trust store or pinned certificate, defaults to Basic256Sha256 with SignAndEncrypt, and fails the connection if the negotiated security policy is weaker than the configured one.

It is possible to read the advisory at lists.apache.org. This vulnerability is uniquely identified as CVE-2026-102508 since 09/29/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/30/2026). The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

Upgrading to version 1.0.0 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• PLC4X

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9

License

• open-source

Website

• Vendor: https://www.apache.org/

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