CVE-2026-45581: Hyperledger Fabric Information Disclosure

CVE-2026-45581 Overview

CVE-2026-45581 affects fabric-chaincode-java, a Java implementation of Hyperledger Fabric chaincode shim APIs. The vulnerability exposes the TLS private key password in plaintext through INFO level logs when chaincode runs in chaincode-as-a-service mode with TLS enabled. The flaw maps to [CWE-532] (Insertion of Sensitive Information into Log File). Versions from 2.3.1 up to but not including 2.5.10 are affected. An attacker with access to the chaincode server logs can recover the TLS private key password. Combined with access to the TLS private key, the attacker can impersonate the chaincode server.

Critical Impact
Exposure of the TLS private key password enables chaincode server impersonation when paired with key file access, breaking the trust boundary between Hyperledger Fabric peers and chaincode services.

Affected Products

fabric-chaincode-java versions 2.3.1 through 2.5.9
Hyperledger Fabric chaincode deployments using chaincode-as-a-service mode with TLS enabled
Java-based chaincode containers leveraging the affected shim APIs

Discovery Timeline

2026-06-08 - CVE-2026-45581 published to NVD
2026-06-09 - Last updated in NVD database

Technical Details for CVE-2026-45581

Vulnerability Analysis

The fabric-chaincode-java library provides the runtime shim that Java chaincode uses to communicate with Hyperledger Fabric peers. When operators deploy chaincode in chaincode-as-a-service (CCaaS) mode, the chaincode runs as a long-lived server that peers connect to over gRPC. TLS protects this channel, and the server loads a TLS private key protected by a password.

During server startup, the chaincode logs configuration information at INFO level. The logging code includes the TLS private key password value in the emitted log line. Anyone who can read these logs sees the password in plaintext.

The scope of the issue is bounded by the attack vector. An attacker needs local access to the log destination, whether file system, container stdout, or a centralized log aggregator. Pairing the password with access to the TLS key file enables full impersonation of the chaincode server to Fabric peers.

Root Cause

The root cause is improper handling of sensitive configuration data in the logging subsystem. The startup routine treats the TLS private key password as a normal configuration field and writes it through standard logging instead of masking or omitting it.

Attack Vector

Exploitation requires local, authenticated access to the chaincode server logs. A malicious operator, a compromised sidecar, or any process with read access to the log stream can extract the password. The CVSS vector AV:L/AC:L/PR:L/UI:N reflects this local prerequisite. Confidentiality is the only directly impacted property; integrity and availability impact arise only when the attacker further obtains the TLS key file and stages an impersonation attack against Fabric peers.

No public proof-of-concept code is required. The vulnerability manifests during normal startup, and the password appears in routine INFO log output. Refer to the Hyperledger GitHub Security Advisory GHSA-wg5x-3g47-v38r for vendor technical details.

Detection Methods for CVE-2026-45581

Indicators of Compromise

Chaincode server log entries at INFO level containing fields associated with TLS key password configuration
Unexpected reads of chaincode container log files or log aggregation indices by non-operator identities
Outbound connections from unauthorized hosts presenting the legitimate chaincode TLS certificate to Fabric peers

Detection Strategies

Scan existing and archived chaincode logs for plaintext password patterns near TLS initialization messages
Compare the deployed fabric-chaincode-java version against the fixed release 2.5.10 across all CCaaS deployments
Audit access control lists on log files, container runtime log drivers, and SIEM indices that ingest chaincode logs

Monitoring Recommendations

Forward chaincode container logs to a centralized platform with role-based access and alert on access by non-administrative principals
Monitor Fabric peer connection metadata for chaincode endpoints that present the same certificate from unexpected source addresses
Track configuration changes in CCaaS deployment manifests, including TLS key references and environment variables holding passwords

How to Mitigate CVE-2026-45581

Immediate Actions Required

Upgrade fabric-chaincode-java to version 2.5.10 or later across all chaincode-as-a-service deployments
Rotate the TLS private key and password for any chaincode server that ran an affected version with logs accessible to additional principals
Restrict and audit read access to historical chaincode logs, then purge logs that contain the exposed password value

Patch Information

The issue is patched in fabric-chaincode-java version 2.5.10. The fix removes the TLS private key password from INFO level log output. Consult the Hyperledger GitHub Security Advisory GHSA-wg5x-3g47-v38r for the upstream release notes and commit references.

Workarounds

Raise the chaincode logging threshold above INFO until the upgrade is applied, accepting the loss of operational visibility
Restrict log file and log aggregator access to a minimal set of administrative accounts using file system permissions and RBAC
Run chaincode-as-a-service containers without TLS password protection on the key file and rely on alternative key protection mechanisms where feasible

bash

# Configuration example
# Upgrade fabric-chaincode-java dependency in Gradle build
# build.gradle
dependencies {
    implementation 'org.hyperledger.fabric-chaincode-java:fabric-chaincode-shim:2.5.10'
}

# Or in Maven pom.xml
# <dependency>
#   <groupId>org.hyperledger.fabric-chaincode-java</groupId>
#   <artifactId>fabric-chaincode-shim</artifactId>
#   <version>2.5.10</version>
# </dependency>

# Restrict access to chaincode container logs (Docker example)
chmod 600 /var/lib/docker/containers/<container-id>/<container-id>-json.log
chown root:root /var/lib/docker/containers/<container-id>/<container-id>-json.log