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:

Gaining access to KNIME Business Hub as a normal user with workflow execution capabilities
Creating a workflow that interacts with the internal Apache Artemis instance
Registering a federated mirror without providing valid authentication credentials
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

bash

# 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