CVE-2026-44911: Apache NiFi Authorization Bypass in Configuration Verification (CVSS 6.3)

Technical summary

The vulnerability stems from insufficient authorization checks in the component configuration verification request handler. NiFi's configuration system allows users with read-level permissions to submit proposed configuration properties as part of verification workflows. These proposed properties are processed without validating that the requestor possesses write access to modify component configuration. An authenticated user with only read privileges can therefore invoke predefined verification methods—functions that test or validate configuration changes—using attacker-controlled property values, effectively achieving unauthorized configuration modification. The issue is classified under CWE-863 (Incorrect Authorization), indicating a logic flaw in access control rather than an authentication bypass. Deployments with properly segregated role-based authorization for read versus write access are affected; installations already enforcing strict separation of duties at the authorization layer remain exposed only if verification methods perform sensitive operations.

Business impact

This vulnerability enables privilege escalation within NiFi clusters. A user granted read-only access—common for operators monitoring workflows or auditors reviewing configurations—can alter component behavior without explicit write privileges. Depending on the component types and verification methods available, an attacker could trigger unintended data flows, manipulate output destinations, modify security settings on processors, or test malicious configurations that would later be applied. In multi-tenant or regulated environments where access controls are foundational to compliance, this represents a control breakdown. The impact is typically limited to confidentiality and integrity of data within the NiFi instance, with potential availability effects if verification methods interact with external systems or trigger resource-intensive operations.

Affected systems

Apache NiFi versions 1.15.0 through 2.9.0 are affected. Organizations running NiFi 1.14.0 or earlier, or those already on 2.10.0 or later, are not impacted. Patch status should be verified against your current deployment version. The vulnerability applies to all installations regardless of operating system or deployment model (standalone, clustered, containerized).

Exploitability

Exploitation requires valid authentication credentials with at least read access to the NiFi instance—a relatively low bar in many operational environments where read access is widely distributed. No user interaction is needed, and the attack can be performed over the network by any authenticated user. The CVSS score of 6.3 (MEDIUM) reflects the requirement for prior authentication and the limited scope of impact, but the ease of execution and low barrier to entry make this a practical risk for organizations with large operator populations or inadequate access governance.

Remediation

Upgrade to Apache NiFi 2.10.0 or later. This version enforces write access requirements for configuration verification requests, closing the authorization gap. Organizations unable to upgrade immediately should audit and restrict read access to component configurations to only users who legitimately require it, implementing additional network segmentation or firewall rules if possible. Consider implementing application-level monitoring to detect unusual verification requests from read-only accounts.

Patch guidance

Verify the version of NiFi deployed in your environment against Apache's advisory documentation. For NiFi 1.15.0 through 2.9.0, plan an upgrade to 2.10.0 or a later version. Review the Apache NiFi release notes for any compatibility considerations or data migration steps required for your version jump. If you are running an older branch (1.14.x or earlier), confirm your version against the affected range. Test the upgrade in a non-production environment first to validate that existing workflows and configurations function as expected post-upgrade.

Detection guidance

Monitor NiFi audit logs and REST API request logs for configuration verification requests originating from users or service accounts with read-only role assignments. Look for repeated verification requests targeting different component types or properties, or requests with unusual property values that differ significantly from current configurations. Inspect the authorization context of such requests to identify whether they were submitted by principals lacking write permissions. Network-based detection could flag unusual API traffic patterns to configuration endpoints from unexpected clients, though this requires visibility into NiFi API traffic.

Why prioritize this

While the CVSS score is MEDIUM (6.3), this vulnerability should be prioritized if your NiFi deployment enforces role-based access control and distributes read access widely. The combination of easy exploitation (authenticated access only, no special conditions), insider-threat risk (read-only users are often numerous), and the potential to bypass access controls makes this a control-plane risk. Organizations with least-privilege access policies or those handling sensitive data transformations should treat this as high priority. Conversely, if your deployment grants read and write access to the same user groups, the practical risk is lower, though still present.

Risk score, explained

The CVSS 3.1 score of 6.3 is driven by the requirement for authenticated access (PR:L), the network-accessible attack vector (AV:N), and low attack complexity (AC:L). The scope is unchanged (S:U), indicating impact is limited to the NiFi application itself. Confidentiality, Integrity, and Availability are each marked as Low (L), reflecting that a read-only user can modify configurations but cannot directly exfiltrate data, completely disable the system, or access other users' data. The score does not account for organizational factors like the breadth of read access distribution or the sensitivity of managed workflows, which should inform your internal risk ranking.

Frequently asked questions