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CVE-2026-42440 high CVSS 7.5

Vulnerability in org.apache.opennlp:opennlp-tools (CVE-2026-42440)

Summary

Vulnerability in org.apache.opennlp:opennlp-tools (CVE-2026-42440). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.0.0-M3 or later.

Original description

The description as published by the source.

OOM Denial of Service via Unbounded Array Allocation in Apache OpenNLP AbstractModelReader 

Versions Affected: 

Before 2.5.9

Before 3.0.0-M3 

Description:

The AbstractModelReader methods getOutcomes(), getOutcomePatterns(), and getPredicates() each read a 32-bit signed integer count field from a binary model stream and pass that value directly to an array allocation (new String[numOutcomes], new int[numOCTypes][], new String[NUM_PREDS]) without validating that the value is non-negative or within a reasonable bound. The count is therefore fully attacker-controlled when the model file originates from an untrusted source.

A crafted .bin model file in which any of these count fields is set to Integer.MAX_VALUE (or any value large enough to exhaust the available heap) triggers an OutOfMemoryError at the array allocation itself, before the corresponding label or pattern data is consumed from the stream. The error occurs very early in deserialization: for a GIS model, getOutcomes() is reached after only the model-type string, the correction constant, and the correction parameter have been read; so the attacker pays no meaningful size cost to weaponize a payload, and a single small file can crash a JVM that loads it. Any code path that deserializes a .bin model is affected, including direct use of GenericModelReader and any higher-level component that delegates to it during model load.

The practical impact is denial of service against processes that load model files from untru…

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-2026-42440 has been found in org.apache.opennlp:opennlp-tools.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade org.apache.opennlp:opennlp-tools to 3.0.0-M3 or later.
If unsure, ask your IT team or search "org.apache.opennlp:opennlp-tools CVE-2026-42440" on the vendor's site.

CVE-2026-42440 (org.apache.opennlp:opennlp-tools) — CWE-789 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.0.0-M3 — 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.

❓ What is the problem

A vulnerability (CWE-789) exists in org.apache.opennlp:opennlp-tools.

📍 Affected scope

Check the vendor advisory for the affected versions of org.apache.opennlp:opennlp-tools.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.0.0-M3.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Apply patch patch 
    Upgrade org.apache.opennlp:opennlp-tools to 3.0.0-M3

    ステージング環境で 3.0.0-M3 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。

  3. 3
    Post-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

maven org.apache.opennlp:opennlp-tools
[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0-M1"},{"fixed":"3.0.0-M3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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