Apache OpenNLP: XXE via Dictionary Parsing in DictionaryEntryPersistor

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Summary

CVECVE-2026-40682
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-04 17:16:23 UTC
Updated2026-05-06 18:00:49 UTC
DescriptionXML External Entity (XXE) via Unsanitized Dictionary Parsing in Apache OpenNLP DictionaryEntryPersistor Versions Affected: before 2.5.9, before 3.0.0-M3 Description: 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. 3.x users should upgrade to 3.0.0-M3. Users who cannot upgrade immediately should ensure that all dictionary files are sourced from trusted origins and should consider wrapping the Dictionary(InputStream) constructor with input validation that rejects any XML containing a DOCTYPE declaration before it reaches the parser.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.000290000 probability, percentile 0.080220000 (date 2026-05-05)

Problem Types: CWE-611 | CWE-611 CWE-611 Improper Restriction of XML External Entity Reference

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Apache Opennlp All All All All
Application Apache Opennlp 3.0.0 m1 All All
Application Apache Opennlp 3.0.0 m2 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache OpenNLP affected 2.5.9 semver Not specified
CNA Apache Software Foundation Apache OpenNLP affected 3.0 3.0.0-M3 semver Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/05/01/19 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
lists.apache.org/thread/r6jpt0qr9nj67gqhppqg7jxf8vsbo0w6 [email protected] lists.apache.org Mailing List, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Subramanian S (en)

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