Apache NiFi users are being urged to upgrade after the project disclosed a high-severity authorization flaw tracked as CVE-2026-25903.
The issue, published on 2026-02-16, can allow a less-privileged authenticated user to modify configuration properties on certain “restricted” extension components that were previously added to a flow by a more privileged user, potentially weakening security controls in environments that rely on tiered permissions.
Authorization Bypass Attacks
According to the Apache NiFi advisory, versions 1.1.0 through 2.7.2 are missing an authorization check when updating configuration properties on extension components that declare specific Required Permissions via the Restricted annotation.
In NiFi, the Restricted annotation is intended to enforce additional privileges for sensitive components, typically because they can interact with the operating system, execute code, access external services, or otherwise perform actions that administrators want tightly controlled.
| CVE ID | Severity | Affected Versions | Description |
|---|---|---|---|
| CVE-2026-25903 | High | 1.1.0 to 2.7.2 | Missing authorization of restricted permissions for extension component property updates, enabling an authorization bypass |
The core of the flaw is a gap between “adding” a restricted component and “updating” it later.
While a more privileged user is required to add a restricted component to the flow configuration, the framework did not verify restricted status when a component already present in the flow is updated.
As a result, a user who lacks the elevated permission needed to add that component could still be able to change its properties after it is in place, creating an authorisation bypass condition for component updates.
Apache notes that not all deployments are equally exposed. Installations that do not implement different authorization levels for Restricted components are not subject to this vulnerability, because the framework’s standard write permissions act as the primary security boundary.
However, environments that deliberately separate duties such as allowing some users to edit flows while reserving restricted-component control to admins should treat this as a meaningful privilege boundary break.
The recommended mitigation is to upgrade to Apache NiFi 2.8.0, which includes the fix.
As a practical hardening step, teams should also review current access policies for flow modification, audit changes to component properties, and validate that restricted components cannot have their settings altered by roles that are intended to be limited.
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