---
id: CVE-2026-102497
title: >-
  The Apache XmlSchema walker (xmlschema-walker) doesn't detect cycles in type
  derivation, substitution groups, model groups or attribute groups
summary: >-
  The Apache XmlSchema walker (xmlschema-walker) doesn't detect cycles in type
  derivation, substitution groups, model groups or attribute groups. A malicious
  schema with such a cycle can make the walker recurse until the stack
  overflows, c…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-674
vendor: apache
product: xmlschema
affected:
  - xmlschema < 2.3.3
patched:
  - xmlschema 2.3.3
published: '2026-09-29'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T14:37:44.453'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102497'
references:
  - url: 'https://lists.apache.org/thread/1cj02tobjyhjqq723bvg78yxkqt1lk7k'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/29/17'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
epss: 0.00528
epssPercentile: 0.44481
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-29T20:13:25.311609Z'
ingestedAt: '2026-09-29T12:33:37.292Z'
---

## Overview

The Apache XmlSchema walker (xmlschema-walker) doesn't detect cycles in type derivation, substitution groups, model groups or attribute groups. A malicious schema with such a cycle can make the walker recurse until the stack overflows, causing a denial of service.

Users are recommended to upgrade to version 2.3.3, which fixes this issue.

## Affected

- `xmlschema < 2.3.3`

## Remediation

Upgrade past the affected range:

- `xmlschema 2.3.3`