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CVE-2026-40682GHSA-4v8g-86x5-3vrc

org.apache.opennlp:opennlp-tools: Apache OpenNLP DictionaryEntryPersistor Vulnerable to XML External Entity (XXE) via Unsanitized Dictionary Parsing

Apache Software Foundation org.apache.opennlp:opennlp-toolsmavenLibraries & packages
Open in ThreatlineRecord JSON
CVSS
9.1Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.84%Chance of exploitation activity in the next 30 days, higher than 57% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in3.0.0-M3Also 2.5.9, 1.9.5GitHub
Published4 May 2026Updated 2 Oct 2026CVE List

What fixes it

  • 3.0.0-M3org.apache.opennlp:opennlp-tools, mavenGitHub<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>3.0.0-M3</version></dependency>
  • 2.5.9org.apache.opennlp:opennlp-tools, mavenGitHub<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>2.5.9</version></dependency>
  • 1.9.5org.apache.opennlp:opennlp-tools, mavenGitHub<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>1.9.5</version></dependency>
  • 2.5.9Apache OpenNLPCVE List
  • 3.0.0-M3Apache OpenNLPCVE List
  • 1.9.5Apache OpenNLPCVE List
Show all 9 fixed versions
  • 2.5.9org.apache.opennlp:opennlp-tools, MavenOSV<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>2.5.9</version></dependency>
  • 3.0.0-M3org.apache.opennlp:opennlp-tools, MavenOSV<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>3.0.0-M3</version></dependency>
  • 1.9.5org.apache.opennlp:opennlp-tools, MavenOSV<dependency><groupId>org.apache.opennlp</groupId><artifactId>opennlp-tools</artifactId><version>1.9.5</version></dependency>

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

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.

Text from GitHub Advisory Database

Affected versions 47

  • org.apache.opennlp:opennlp-tools, maven>= 3.0.0-M1, < 3.0.0-M3GitHub
  • org.apache.opennlp:opennlp-tools, maven>= 2.0.0, < 2.5.9GitHub
  • org.apache.opennlp:opennlp-tools, maven< 1.9.5GitHub
  • Apache OpenNLPaffected: 2.0 before 2.5.9CVE List
  • Apache OpenNLPaffected: 3.0.0-M1 before 3.0.0-M3CVE List
  • Apache OpenNLPaffected: all versions before 1.9.5CVE List
  • org.apache.opennlp:opennlp-tools, Mavenfrom 2.0.0, fixed in 2.5.9OSV
  • org.apache.opennlp:opennlp-tools, Maven2.0.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.1.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.1.1OSV
  • org.apache.opennlp:opennlp-tools, Maven2.2.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.3.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.3.1OSV
  • org.apache.opennlp:opennlp-tools, Maven2.3.2OSV
  • org.apache.opennlp:opennlp-tools, Maven2.3.3OSV
  • org.apache.opennlp:opennlp-tools, Maven2.4.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.0OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.1OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.2OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.3OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.4OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.5OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.6OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.6.1OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.7OSV
  • org.apache.opennlp:opennlp-tools, Maven2.5.8OSV
  • org.apache.opennlp:opennlp-tools, Mavenfrom 3.0.0-M1, fixed in 3.0.0-M3OSV
  • org.apache.opennlp:opennlp-tools, Maven3.0.0-M1OSV
  • org.apache.opennlp:opennlp-tools, Maven3.0.0-M2OSV
  • org.apache.opennlp:opennlp-tools, Mavenfrom first release, fixed in 1.9.5OSV
  • org.apache.opennlp:opennlp-tools, Maven1.5.1-incubatingOSV
  • org.apache.opennlp:opennlp-tools, Maven1.5.2-incubatingOSV
  • org.apache.opennlp:opennlp-tools, Maven1.5.3OSV
  • org.apache.opennlp:opennlp-tools, Maven1.6.0OSV
  • org.apache.opennlp:opennlp-tools, Maven1.7.0OSV
  • org.apache.opennlp:opennlp-tools, Maven1.7.1OSV
  • org.apache.opennlp:opennlp-tools, Maven1.7.2OSV
  • org.apache.opennlp:opennlp-tools, Maven1.8.0OSV
  • org.apache.opennlp:opennlp-tools, Maven1.8.1OSV
  • org.apache.opennlp:opennlp-tools, Maven1.8.2OSV
  • org.apache.opennlp:opennlp-tools, Maven1.8.3OSV
  • org.apache.opennlp:opennlp-tools, Maven1.8.4OSV
  • org.apache.opennlp:opennlp-tools, Maven1.9.0OSV
  • org.apache.opennlp:opennlp-tools, Maven1.9.1OSV
  • org.apache.opennlp:opennlp-tools, Maven1.9.2OSV
  • org.apache.opennlp:opennlp-tools, Maven1.9.3OSV
  • org.apache.opennlp:opennlp-tools, Maven1.9.4OSV

References 6