XXE (XML External Entity) in org.apache.opennlp:opennlp-tools (CVE-2026-40682)
Summary
Vulnerability in org.apache.opennlp:opennlp-tools (CVE-2026-40682). Confidential information can be exposed externally. Mitigation: upgrade to 1.9.5 or later.
Original description
The description as published by the source.
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 Di…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-40682 has been found in org.apache.opennlp:opennlp-tools.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade org.apache.opennlp:opennlp-tools to 1.9.5 or later.
If unsure, ask your IT team or search "org.apache.opennlp:opennlp-tools CVE-2026-40682" on the vendor's site.
CVE-2026-40682 (org.apache.opennlp:opennlp-tools) — CWE-611 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 1.9.5 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-611) exists in org.apache.opennlp:opennlp-tools.
Check the vendor advisory for the affected versions of org.apache.opennlp:opennlp-tools.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
Update to 1.9.5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで org.apache.opennlp:opennlp-tools を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade org.apache.opennlp:opennlp-tools to 1.9.5ステージング環境で 1.9.5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-40682 apache-opennlp
- Ubuntu UBUNTU-CVE-2026-40682 apache-opennlp
References
- advisory nvd.nist.gov
- package github.com
- web lists.apache.org
- web openwall.com
- web github.com
- web access.redhat.com
- web bugzilla.redhat.com
- web security.access.redhat.com