CVE-2026-41871: Apache Nutch: Unauthenticated reflection-based job execution in Nutch Server (Nutch REST API)
Missing Authorization, Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') vulnerability in Apache Nutch Server (Nutch REST API).
This issue affects Apache Nutch: from 1.10 through 1.22.
Users are recommended to upgrade to version 1.23, which removes the Nutch Server. If an upgrade is not possible, user must restrict access to instances running the Nutch Service to trusted users only. Please, also visit the Apache Nutch security advisories https://nutch.apache.org/documentation/security/ .
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache Nutch Server (Nutch REST API)to a version that resolves this vulnerability.Fixed in 1.23 - Compensating control
If upgrade is not possible, restrict access to instances running the Nutch Service (Nutch REST API / Nutch ST API) to trusted users only.
Event History
Frequently Asked Questions
Which deployments are exposed?
Apache Nutch installations running Nutch Server, including the Nutch REST API, are affected from version 1.10 through 1.22. The issue concerns instances running the Nutch Service.
What access does an attacker need to exploit this issue?
The vulnerable Nutch Server functionality is unauthenticated, so access to the exposed service is the relevant prerequisite. Restricting service access to trusted users is the documented mitigation when an upgrade cannot be performed.
What should be done if upgrading is not immediately possible?
Restrict access to instances running the Nutch Service so that only trusted users can reach them. The recommended remediation is upgrading to version 1.23, which removes Nutch Server.