CVE-2026-91858
Received Received - Intake

XML External Entity Processing in Apache Camel FOP

Publication date: 2026-10-19

Last updated on: 2026-10-19

Assigner: Apache Software Foundation

Description
FopProducer transforms the incoming XSL-FO message body by creating a javax.xml.transform.TransformerFactory through TransformerFactory.newInstance() and enabling only FEATURE_SECURE_PROCESSING before running an identity transform over the body. On the JDK's built-in transformer, that feature alone already empties the accessExternalDTD and accessExternalStylesheet limits, so an external DTD or entity is refused. When a third-party JAXP TransformerFactory such as Saxon-HE is on the classpath, for example because the application also uses camel-xslt-saxon or camel-saxon, TransformerFactory.newInstance() returns that implementation instead, and FEATURE_SECURE_PROCESSING on its own does not restrict external resource access on it. A DOCTYPE with an external subset, or an external general entity, declared in the XSL-FO document is then resolved and expanded while the body is transformed. An external sender whose XSL-FO reaches a fop producer could therefore read files readable by the Camel process and cause the process to issue requests to hosts the document names. camel-fop does not bring such a factory itself, and excludes Xalan, so a default deployment using the JDK transformer is not affected; the issue is reachable only where another component has placed an alternative JAXP TransformerFactory on the classpath. Releases on the 4.14.x line and earlier reached end of life before this issue was resolved and do not receive a fix.

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Meta Information

Published
2026-10-19
Last Modified
2026-10-19
Generated
2026-10-19
AI Q&A
2026-10-19
EPSS Evaluated
N/A
NVD
CVE-2026-91858
EUVD
EUVD-2026-104208

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
Apache Software Foundation Apache Camel 4.0.0
Apache Software Foundation Apache Camel 4.19.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-611 The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

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Executive Summary

This vulnerability involves Apache Camel's FopProducer component improperly handling XSL-FO document processing. When a third-party JAXP TransformerFactory like Saxon-HE is used, the FEATURE_SECURE_PROCESSING setting does not restrict external resource access. This allows malicious XSL-FO documents with external DTDs or entities to read local files or make network requests.

Impact Analysis

An attacker could exploit this to read sensitive files accessible by the Camel process or initiate unauthorized network requests. This could lead to data breaches, information disclosure, or potential denial-of-service if the process interacts with malicious hosts.

Compliance Impact

This vulnerability could violate GDPR by exposing personal data through unauthorized file access or network requests. For HIPAA, it may lead to unauthorized access to protected health information. Compliance failures could result in legal penalties and reputational damage.

Mitigation Strategies

Check if a third-party JAXP TransformerFactory like Saxon-HE is on the classpath. If present, remove it or ensure FEATURE_SECURE_PROCESSING is properly configured to restrict external resource access.

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