CVE-2026-4649: KNIME Business Hub Auth Bypass Vulnerability

CVE-2026-4649 Overview

CVE-2026-4649 is an authentication bypass vulnerability affecting Apache Artemis before version 2.52.0, which impacts KNIME Business Hub deployments. The flaw allows authenticated users with workflow execution privileges to bypass authentication mechanisms and gain unauthorized access to internal message broker communications. An attacker can install and register a federated mirror without authentication to the original Apache Artemis instance, enabling them to read all internal messages and inject new messages into the broker.

Critical Impact

Authenticated users with workflow execution capabilities can read all messages exchanged via the broker and inject malicious messages, potentially compromising data integrity and confidentiality across the KNIME Business Hub environment.

Affected Products

• KNIME Business Hub (all versions prior to 1.18.0, 1.17.4, and 1.16.3)
• Apache Artemis (versions prior to 2.52.0)

Discovery Timeline

• 2026-03-24 - CVE-2026-4649 published to NVD
• 2026-03-24 - Last updated in NVD database

Technical Details for CVE-2026-4649

Vulnerability Analysis

This vulnerability falls under CWE-306 (Missing Authentication for Critical Function), indicating that the Apache Artemis message broker fails to enforce proper authentication for certain critical operations. While Apache Artemis is not directly exposed to external networks in KNIME Business Hub deployments, the internal exposure creates a significant risk for authenticated users who can execute workflows.

The attack requires the attacker to have at least normal user privileges and the ability to execute workflows in an executor. From this position, a malicious actor can leverage the authentication bypass to establish unauthorized connections to the message broker infrastructure.

Root Cause

The root cause stems from missing authentication enforcement in the Apache Artemis federated mirror registration process. The broker accepts mirror registrations without validating the identity or authorization of the requesting entity, allowing any user with network access to the internal Artemis instance to establish unauthorized connections.

Attack Vector

The attack is network-based and requires authenticated access to the KNIME Business Hub with workflow execution privileges. An attacker exploits the vulnerability by:

1. Gaining access to KNIME Business Hub as a normal user with workflow execution capabilities
2. Creating a workflow that interacts with the internal Apache Artemis instance
3. Registering a federated mirror without providing valid authentication credentials
4. Intercepting all messages passing through the broker or injecting malicious messages

The vulnerability mechanism involves the federated mirror registration endpoint accepting connections without proper credential validation. Attackers leverage this to establish an unauthorized mirror that receives copies of all messages and can inject new messages into the broker queue. For detailed technical analysis, refer to the KNIME Security Advisory.

Detection Methods for CVE-2026-4649

Indicators of Compromise

• Unexpected federated mirror registrations in Apache Artemis logs
• Unusual workflow execution patterns attempting to access internal messaging infrastructure
• Unauthorized connections to the Artemis broker from executor environments
• Anomalous message injection or duplication in broker queues

Detection Strategies

• Monitor Apache Artemis logs for federated mirror registration events from unauthorized sources
• Implement network segmentation monitoring to detect unexpected connections to internal broker services
• Review workflow execution logs for suspicious patterns targeting internal infrastructure
• Deploy endpoint detection to identify unusual process behavior in executor environments

Monitoring Recommendations

• Enable detailed logging for Apache Artemis federation events and connection attempts
• Configure alerts for new mirror registrations that do not match expected infrastructure patterns
• Implement audit trails for all workflow executions with network access to internal services
• Monitor message broker queue statistics for unexpected message volume changes

How to Mitigate CVE-2026-4649

Immediate Actions Required

• Upgrade KNIME Business Hub to version 1.18.0, 1.17.4, or 1.16.3 depending on your deployment track
• Review recent workflow execution logs for potential exploitation attempts
• Audit existing federated mirror configurations in Apache Artemis
• Restrict workflow execution privileges to trusted users only until patching is complete

Patch Information

KNIME has released fixed versions that include an updated Apache Artemis package (2.52.0 or later) with proper authentication enforcement for federated mirror operations. The following KNIME Business Hub versions contain the fix:

• Version 1.18.0 (latest track)
• Version 1.17.4 (1.17.x track)
• Version 1.16.3 (1.16.x track)

For additional details, consult the KNIME Security Advisory.

Workarounds

• No official workarounds are available for this vulnerability
• KNIME recommends updating to a fixed version as soon as possible
• As a temporary measure, restrict workflow execution privileges to minimize the attack surface
• Consider implementing additional network segmentation around the Apache Artemis broker if upgrading is not immediately possible

# Verify KNIME Business Hub version
kubectl get pods -n knime -o jsonpath='{.items[*].spec.containers[*].image}' | tr ' ' '\n' | grep knime

# Check Apache Artemis version in deployment
kubectl exec -n knime <artemis-pod-name> -- cat /opt/artemis/lib/artemis-server-*.jar | head -1