CVE-2026-102496: Apache XMLSchema: Denial of service through deeply nested schema structures

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

Apache XmlSchema doesn't limit how deeply schema structures can be nested when it builds its schema model, so a malicious schema can make parsing recurse until the stack overflows. This causes 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/9z1vg8wmvwpfw748fb2nb55w4hgbnxol
http://www.openwall.com/lists/oss-security/2026/09/29/16

Get alerted when CVE-2026-102496 or the next vulnerability affects your stack