CVE-2026-42402: Apache Neethi DoS via Policy Normalization
The National Vulnerability Database has disclosed CVE-2026-42402, a high-severity Denial of Service (DoS) vulnerability impacting Apache Neethi. The flaw, assigned a CVSS score of 7.5, stems from algorithmic complexity in the policy normalization process, specifically an unbounded Cartesian cross-product expansion.
Attackers can exploit this by crafting malicious WS-Policy documents. These specially designed policies trigger an exponential expansion during normalization, leading to excessive memory allocation that exhausts the Java Virtual Machine (JVM) heap. This effectively crashes the service, creating a Denial of Service condition for applications utilizing Apache Neethi.
Defenders must prioritize upgrading Apache Neethi to version 3.2.2. This critical update introduces limits on the maximum number of normalized policy alternatives, mitigating the unbounded memory allocation issue and preventing these DoS attacks. Ignoring this patch leaves systems vulnerable to straightforward, impactful service disruptions.
What This Means For You
- If your organization uses Apache Neethi, you are exposed to a high-severity Denial of Service vulnerability (CVE-2026-42402). This isn't theoretical; a simple crafted policy document can bring down your service. Check your deployments and upgrade to version 3.2.2 immediately to prevent service outages.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42402: Apache Neethi DoS via Algorithmic Complexity
title: CVE-2026-42402: Apache Neethi DoS via Algorithmic Complexity
id: scw-2026-05-01-ai-1
status: experimental
level: high
description: |
Detects attempts to exploit CVE-2026-42402 by sending specially crafted WS-Policy documents to the Apache Neethi normalization endpoint. This can trigger an exponential Cartesian cross-product expansion, leading to unbounded memory allocation and JVM heap exhaustion (Denial of Service).
author: SCW Feed Engine (AI-generated)
date: 2026-05-01
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42402/
tags:
- attack.impact
- attack.t1499
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/neethi/normalize'
cs-method:
- 'POST'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42402 | DoS | Apache Neethi |
| CVE-2026-42402 | DoS | Apache Neethi versions prior to 3.2.2 |
| CVE-2026-42402 | DoS | Algorithmic complexity in policy normalization |
| CVE-2026-42402 | DoS | Specially crafted WS-Policy documents causing exponential Cartesian cross-product expansion |
| CVE-2026-42402 | DoS | Unbounded memory allocation during policy normalization |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 01, 2026 at 12:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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