7.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-42403

CVE-2026-42403: Apache Neethi does not properly detect circular references in policy definitions.

Apache Neethi does not properly detect circular references in policy definitions. When a WS-Policy document contains circular policy references (where Policy A references Policy B which references Policy A), the policy normalization process can enter an infinite loop or cause excessive recursion, leading to a stack overflow or application hang. An attacker can craft malicious policy documents with circular references to cause a Denial of Service condition

Users are recommended to upgrade to version 3.2.2, which fixes this issue.

(GitHub Advisory)

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CVE-2026-42403

CVE-2026-42403:

7.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
org.apache.neethi:neethi	maven	< 3.2.2	3.2.2

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The analysis of the security vulnerability in Apache Neethi (CVE-2026-42403) reveals two primary weaknesses in the policy normalization process, both residing within the org.apache.neethi.AbstractPolicyOperator class. These weaknesses could be exploited to cause a Denial of Service (DoS).

The first vulnerability is an infinite recursion issue caused by a lack of circular reference detection. The normalizeOperator function, which recursively processes policy references, did not track the policies it was currently resolving. An attacker could create a policy structure where Policy A references Policy B, and Policy B references Policy A. When normalize is called on such a policy, it leads to unbounded recursion in normalizeOperator, ultimately causing a StackOverflowError. The patch addresses this by adding a Set to track the IDs of policies being resolved, thus detecting and preventing the circular reference.

The second vulnerability is an uncontrolled resource consumption issue within the getCrossProduct function. This function can be forced to generate a Cartesian product of policy alternatives that grows exponentially. An attacker could craft a policy that triggers this exponential expansion, leading to excessive heap memory allocation and an OutOfMemoryError. The fix introduces a hard limit (MAX_ALTERNATIVES) on the number of policy alternatives that can be generated, preventing this resource exhaustion attack.

Therefore, the key functions that would appear in a runtime profile during exploitation are org.apache.neethi.AbstractPolicyOperator.normalize, which initiates the process, and the two core vulnerable functions it calls into: org.apache.neethi.AbstractPolicyOperator.normalizeOperator for the recursion-based DoS and org.apache.neethi.AbstractPolicyOperator.getCrossProduct for the memory-exhaustion-based DoS.

Vulnerable functions

org.apache.neethi.AbstractPolicyOperator.normalizeOperator

src/main/java/org/apache/neethi/AbstractPolicyOperator.java

This function recursively processes policy components. Prior to the patch, it lacked detection for circular references. When processing a policy with a circular reference (e.g., Policy A refers to Policy B, which in turn refers back to Policy A), this function would enter an infinite recursion, leading to a StackOverflowError and a denial of service. The patch introduces a 'resolving' set to track policies currently being processed, breaking the loop if a cycle is detected.

org.apache.neethi.AbstractPolicyOperator.normalize

src/main/java/org/apache/neethi/AbstractPolicyOperator.java

This function is the entry point for the policy normalization process. It initiates the recursive normalization by calling `normalizeOperator`. A malicious policy designed to exploit the circular reference vulnerability would be passed to this function, triggering the infinite recursion in `normalizeOperator`.

org.apache.neethi.AbstractPolicyOperator.getCrossProduct

src/main/java/org/apache/neethi/AbstractPolicyOperator.java

This function is responsible for computing the cross product of different policy alternatives. A specially crafted policy could cause this function to generate an exponentially large number of alternatives, consuming excessive memory and leading to an OutOfMemoryError, resulting in a denial of service. The patch mitigates this by introducing a limit (`MAX_ALTERNATIVES`) on the number of alternatives that can be created.

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WAF Rule

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Reasoning

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