What’s Vulnerable › Vulnerabilities

CVE-2026-102497: Apache XMLSchema: Denial of service through cyclic schema definitions in the schema walker

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-29 · updated 2026-10-06
• Weakness: CWE-674

Description

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 products

• Apache Software Foundation Apache XMLSchema: before 2.3.3 — fixed in 2.3.3

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache XMLSchema 2.3.3. Check the vendor advisory for mitigations.

References

• https://lists.apache.org/thread/1cj02tobjyhjqq723bvg78yxkqt1lk7k
• http://www.openwall.com/lists/oss-security/2026/09/29/17

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