CVE-2026-91866: Apache Neethi: Crafted policies cause unbounded work during intersection leading to denial of service

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-21 · updated 2026-09-25
Weakness: CWE-770

Description

A specially crafted pair of WS-Policy documents can force Neethi's policy-intersection to do exponential amounts of work, pinning the CPU for a long time (denial of service). Users are recommended to upgrade to version 3.2.4, which fixes this issue.

Affected products

Apache Software Foundation Apache Neethi: before 3.2.4 — fixed in 3.2.4

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Neethi 3.2.4. Check the vendor advisory for mitigations.

References

https://lists.apache.org/thread/zbfxnomgvbmqchqjgc6lk5h0z76k3gh4
http://www.openwall.com/lists/oss-security/2026/09/18/13

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