CVE-2026-45581: Hyperledger Fabric Java Chaincode TLS Password Exposure in Logs

Technical summary

fabric-chaincode-java versions 2.3.1 to 2.5.9 inadvertently log the TLS private key password at INFO severity when chaincode-as-a-service mode operates with TLS enabled. The exposure occurs during the initialization or configuration phase of the chaincode server. An attacker positioned to read application logs (e.g., via container log aggregation, filesystem access, or log forwarding systems) can extract this plaintext credential. Combined with theft or compromise of the TLS private key file itself, the attacker gains the ability to create valid TLS connections and impersonate the chaincode service to the Fabric network. This represents a credential exposure vulnerability classified under CWE-532 (Insertion of Sensitive Information into Log File).

Business impact

Organizations running Hyperledger Fabric production networks with Java-based chaincodes in chaincode-as-a-service mode face credential exposure risk. The impact depends on log access scope: if logs are centralized, shared with support teams, or stored in cloud logging systems, the attack surface widens. Successful impersonation of a chaincode server could allow an attacker to execute unauthorized smart contract logic, corrupt ledger state, or deny legitimate transaction processing—directly threatening data integrity and network availability in financial, supply chain, or identity-critical deployments.

Affected systems

Hyperledger Fabric chaincode deployments using fabric-chaincode-java versions 2.3.1 through 2.5.9 in chaincode-as-a-service mode with TLS enabled. The vulnerability does not affect earlier versions (pre-2.3.1) or deployments using alternative chaincode runtimes (Go, Node.js). Only systems with both TLS enabled and INFO-level logging active are exposed.

Exploitability

Exploitability is moderate and requires two conditions: (1) the attacker must have read access to chaincode server logs (local, centralized, or forwarded), and (2) the attacker must separately obtain the TLS private key file. The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H) reflects local attack vector and low complexity, though the requirement for multiple artifacts and privilege to access logs limits opportunistic exploitation. No public exploit code or active exploitation has been reported.

Remediation

Upgrade fabric-chaincode-java to version 2.5.10 or later. This patch removes the plaintext password logging and is the definitive fix. Organizations unable to upgrade immediately should rotate TLS private keys and passwords, restrict log access to trusted personnel only, and monitor logs for any signs of unauthorized credential extraction. Consider disabling INFO-level logging temporarily if permitted by operational monitoring needs.

Patch guidance

Apply fabric-chaincode-java version 2.5.10 or later to all chaincode deployments in your environment. Verify the upgrade by checking the library version in your build artifacts and testing chaincode initialization to confirm no plaintext credentials appear in logs at INFO severity. If using a dependency management system (Maven, Gradle), update your pom.xml or build.gradle to reference the patched version, rebuild, and re-deploy chaincodes. Test in a staging environment first to ensure no functional regressions.

Detection guidance

Review historical INFO-level logs from fabric-chaincode-java deployments (2.3.1–2.5.9) for plaintext strings matching TLS password patterns or secrets. Monitor current logs for any plaintext credential material in chaincode server initialization messages. Use log scanning tools to detect common password keywords (e.g., 'password=', 'secret=', 'key=') in INFO logs. Check access logs to identify who has read logs and when; correlate with access to TLS private key files. Implement log redaction rules to mask sensitive fields going forward.

Why prioritize this

Although CVSS 5.5 (MEDIUM) reflects local-only attack vector, the vulnerability is prioritized for timely remediation because it directly exposes cryptographic credentials in widely-accessible log streams. In environments where logs are centralized, exported to cloud services, or retained for compliance purposes, the practical risk of exposure is higher than the base score suggests. Chaincode impersonation could compromise ledger integrity and network trust. Organizations should treat this as a near-term priority, particularly for networks processing high-value transactions.

Risk score, explained

CVSS 3.1 score of 5.5 (MEDIUM) reflects a high confidentiality impact (C:H) but no integrity or availability impact from the logging flaw itself. The local attack vector (AV:L) and requirement for low privilege (PR:L) limit the pool of attackers but acknowledge that many staff and service accounts in production environments hold log-reading privileges. The severity would be elevated if log exposure were combined with key compromise, which is a separate concern requiring defense-in-depth (key rotation, access controls, HSM storage).

Frequently asked questions