OpenNLP 2.5.9

Apache OpenNLP 2.5.9

This is a maintenance and security release on the 2.x line. It backports the security fixes shipped in 3.0.0-M3 and refreshes several dependencies.

Security Fixes

Three security issues are addressed in this release (also fixed in 3.0.0-M3 on the 3.x line).

XXE in DictionaryEntryPersistor (OPENNLP-1819)

The DictionaryEntryPersistor previously used a SAXParserFactory that did not enable secure processing or disable DTD handling, leaving external entity resolution active. A malicious dictionary file could exploit this for local file disclosure or SSRF before any dictionary entry was processed.

The parsing path is now aligned with the project's existing XmlUtil helper, which properly sets FEATURE_SECURE_PROCESSING and disallow-doctype-decl.

Arbitrary Class Instantiation in ExtensionLoader (OPENNLP-1820)

ExtensionLoader.instantiateExtension() performed its isAssignableFrom type check after Class.forName() had already executed the target class's static initializer, allowing a crafted model archive to trigger the static initializer of any class on the classpath.

The fix introduces a package-prefix allowlist consulted before Class.forName() is invoked:

• Classes under opennlp.* remain permitted by default.
• Other packages must be opted in via ExtensionLoader.registerAllowedPackage(String) or the OPENNLP_EXT_ALLOWED_PACKAGES system property (comma-separated list).

OOM via Unbounded Array Allocation in AbstractModelReader (OPENNLP-1821)

getOutcomes(), getOutcomePatterns(), and getPredicates() read attacker-controlled 32-bit count fields from binary model streams and passed them directly to array allocations. A crafted .bin file could trigger an immediate OutOfMemoryError and crash the JVM.

Each count is now bounded (default 10,000,000, configurable via -DOPENNLP_MAX_ENTRIES=<n>), with negative or oversized values failing fast via IllegalArgumentException.

⚠️ For all three issues, users who cannot upgrade immediately should restrict input (dictionary and model files) to trusted sources only.

What's Changed

• Apache OpenNLP 2.5.8 by @mawiesne in #1004
• [2.x]: OPENNLP-1817: Update log4j2 to 2.25.4 by @dependabot[bot] in #999
• [2.x] Regenerated NOTICE file after dependency changes by @github-actions[bot] in #1008
• [2.x]: Bump actions/cache from 5.0.4 to 5.0.5 by @dependabot[bot] in #1018
• [2.x]: Bump com.ruleoftech:markdown-page-generator-plugin from 2.4.2 to 2.4.3 by @dependabot[bot] in #1015
• [2.x]: Bump peter-evans/create-pull-request from 8.1.0 to 8.1.1 by @dependabot[bot] in #1013
• [2.x] OPENNLP-1819: Align DictionaryEntryPersistor XML parsing with XmlUtil by @rzo1 in #1020
• [2.x]: OPENNLP-1822: Update ONNX runtime to 1.25.0 by @dependabot[bot] in #1023
• [2.x] Regenerated NOTICE file after dependency changes by @github-actions[bot] in #1026

Full Changelog: https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12311215&version=12356814