Critical9.1Apache Software Foundation

Critical [CVE-2026-40682] Apache OpenNLP DictionaryEntryPersistor: XML External Entity (XXE)

This critical-severity Apache Software Foundation advisory covers CVE-2026-40682 affecting Apache OpenNLP DictionaryEntryPersistor.

CVE-2026-40682 Published May 4, 2026Updated by vendor Jun 30, 2026

CVE-2026-40682

Affected products & platforms

Apache Software FoundationUnclassified

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Summary

XML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor

Versions Affected: before 2.5.9, before 3.0.0-M3

The DictionaryEntryPersistor class initializes a static SAXParserFactory at class-load time without enabling FEATURE_SECURE_PROCESSING or disabling DTD processing. When create(InputStream, EntryInserter) is invoked, the only feature set on the XMLReader is namespace support — external entity resolution and DOCTYPE declarations remain fully enabled.

An attacker who can supply a crafted dictionary file (e.g., a stop-word list or domain dictionary) containing a malicious DOCTYPE declaration can trigger local file disclosure via file:// entity references or server-side request forgery via http:// entity references during SAX parsing, before the application processes a single dictionary entry.

This is inconsistent with the project's own XmlUtil.createSaxParser() helper, which correctly sets FEATURE_SECURE_PROCESSING and disallow-doctype-decl and is used by all other XML parsing paths in the codebase.

The public Dictionary(InputStream) constructor delegates directly to this method and is the documented API for loading user-supplied dictionaries, making untrusted input a realistic scenario.

Mitigation: 2.x users should upgrade to 2.5.9.

Affected versions

2.5.9
3.0.0

Official advisory · high-confidence parse· fetched 1 month ago·verify at source

Fixed versions

2.5.9
3.0.0-M3

Official advisory · high-confidence parse· fetched 1 month ago·verify at source

Mitigation

Upgrade to a fixed release: 2.5.9, 3.0.0-M3. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 1 month ago·verify at source

Sources

Official and corroborating records used to build this advisory.

CVE.org CNA affected-product recordCVE.org
Structured CNA affected[] data independently confirmed the affected product scope; native advisory content remains authoritative.
CVE Program
NVD discovery recordNVD
Independent discovery and scoring cross-reference. Vendor remediation guidance takes precedence. Discovered from the machine-readable feed https://services.nvd.nist.gov/rest/json/cves/2.0; this link opens the NVD record for CVE-2026-40682 instead of the raw feed document.
NIST National Vulnerability Database

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-40682NVD CVE.org MITRE

Official resources

ASF Security — reporting & CVE process
Official documentation
The Apache Software Foundation's official security page: how ASF CVEs are published and where each project's advisories live.
Apache project downloads (fixed releases)
Official documentation
Official ASF download tree — fetch the fixed release named in this advisory from the project's directory.

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