CVE-2026-41871: Apache Nutch: Unauthenticated reflection-based job execution in Nutch Server (Nutch REST API)

CVE-2026-41871 is a missing-authorization flaw (CWE-862) combined with unsafe reflection (CWE-470) in the Nutch Server component, i.e., the Nutch REST API, affecting Apache Nutch versions 1.10 through 1.22. The REST API fails to properly authorize requests, so unauthenticated or untrusted users can send API calls whose externally controlled input determines which classes or code are loaded and executed. An attacker who can reach the exposed Nutch Server can therefore trigger reflection-based job execution, potentially running arbitrary classes or jobs on the server. Only deployments running the optional Nutch Server (REST API) on Nutch 1.10 through 1.22 are affected. There is currently no public proof of concept, no known in-the-wild exploitation, and the issue is not in CISA KEV; the CVSS score has not yet been assigned.

Do: Upgrade to Apache Nutch 1.23, which removes the vulnerable Nutch Server component. If upgrading is not possible, restrict access to any instance running the Nutch Service/REST API to trusted users only, e.g., via firewall rules, ACLs, or an authenticating reverse proxy. Check whether any Nutch Server instances are exposed beyond trusted networks and review the Apache Nutch security advisories page for updates.