What is CVE-2026-41871?

CVE-2026-41871 is a critical-severity vulnerability in Apache Nutch, classified under Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection). CVSS score: 9.8/10. Published 2026-09-09.

How severe is CVE-2026-41871?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Auth bypass in Apache Nutch

CVE-2026-41871

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/ .

Published 2026-09-09 · last modified 2026-09-10.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (54.3th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Weakness classification (CWE)

References

lists.apache.org/thread/rbr63fx8vlrhzrfknq2l0mg0d0blsl54 (vendor-advisory, Mailing List, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-41871?: CVE-2026-41871 is a critical-severity vulnerability in Apache Nutch, classified under Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection). CVSS score: 9.8/10. Published 2026-09-09.
How severe is CVE-2026-41871?: Critical severity. CVSS v3 base score is 9.8 out of 10.