High severity · published Sep 29, 2026
CVE-2026-102496
Apache XMLSchema: Denial of service through deeply nested schema structures
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AX
Apache XMLSchema · Apache Software Foundation
before 2.3.3 · source: vendor
XM
Xmlschema · Apache
before 2.3.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102496
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102496
vendor-advisory
https://lists.apache.org/thread/9z1vg8wmvwpfw748fb2nb55w4hgbnxol
More from Apache XMLSchema
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CVE-2026-102497
Apache XMLSchema: Denial of service through cyclic schema definitions in the schema walker
7.5
CVE-2026-102495
Apache XMLSchema: Denial of service through unbounded recursion when resolving schema imports and includes