---
id: CVE-2026-40682
title: >-
  XML 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
  SAXParserFa…
summary: >-
  XML 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
  SAXParserFa…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-611
vendor: apache
product: opennlp
affected:
  - opennlp < 2.5.9
  - opennlp = 3.0.0
patched:
  - opennlp 2.5.9
published: '2026-05-04'
updated: '2026-06-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-40682'
references:
  - url: 'https://lists.apache.org/thread/r6jpt0qr9nj67gqhppqg7jxf8vsbo0w6'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/05/01/19'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00495
epssPercentile: 0.41585
ingestedAt: '2026-06-29T21:48:47.447Z'
---

## Overview

XML 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.

## Affected

- `opennlp < 2.5.9`
- `opennlp = 3.0.0`

## Remediation

Upgrade past the affected range:

- `opennlp 2.5.9`