Apache XMLSchema: Denial of service through cyclic schema definitions in the schema walker
Published Sep 29, 2026
7.5
HIGHCVSS 3.1
EPSS 0.36%
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
-
- Version 0StatusaffectedConstraints<2.3.3
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Apache Software Foundation | Apache XMLSchema | unaffected |
|
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Sep 29, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.36% (0.00363) | 27.86th | v5 (v2026.06.15) |
| Oct 1, 2026 | 0.36% (0.00363) | 27.77th | v5 (v2026.06.15) |
References (1)
- https://lists.apache.org/thread/1cj02tobjyhjqq723bvg78yxkqt1lk7k vendor-advisory
| Link | Providers | Tags |
|---|---|---|
| https://lists.apache.org/thread/1cj02tobjyhjqq723bvg78yxkqt1lk7k | vendor-advisory |
Change history (0)
No recorded changes yet.