Is CVE-2026-63317 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-63317 being exploited in the wild.

How severe is CVE-2026-63317?

Informational severity, with a CVSS score of 0, published 24 July 2026.

Which products and versions are affected?

Apache OpenNLP before 2.5.10, before 3.0.0-M5.

Is there a fix for CVE-2026-63317?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-63317 attacked?

It is attacked over the network or with local access, in a software library.

Am I affected by CVE-2026-63317?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-63317: Apache OpenNLP arbitrary class instantiation in XML Feature Generator

CVE-2026-63317 · Severity: info · CVSS 0 · Published 2026-07-24

Apache OpenNLP, a machine learning library for processing natural language text, contains a vulnerability that allows the application to instantiate arbitrary Java classes. An attacker could exploit this by providing a specially crafted model file or a malicious format name, potentially leading to unauthorized actions like network connections or file access if dangerous classes exist on the system. Organizations should upgrade to the latest version to ensure only approved, safe components are loaded by the software.

Quick answers

Is CVE-2026-63317 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-63317 being exploited in the wild.
How severe is CVE-2026-63317?: Informational severity, with a CVSS score of 0, published 24 July 2026.
Which products and versions are affected?: Apache OpenNLP before 2.5.10, before 3.0.0-M5.
Is there a fix for CVE-2026-63317?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-63317 attacked?: It is attacked over the network or with local access, in a software library.
Am I affected by CVE-2026-63317?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

Apache OpenNLP before versions 2.5.10 and 3.0.0-M5 contains three code paths (GeneratorFactory, StreamFactoryRegistry, and StringInterners) that use Class.forName() to load and instantiate classes by name without validation. An attacker who can supply a crafted model archive or an untrusted format name can control the class name being instantiated. While this is not direct remote code execution, it allows an attacker to trigger side effects such as JNDI lookups, outbound network I/O, or filesystem access if a suitable 'gadget' class with a no-arg constructor or static initializer is present on the classpath. The fix introduces a package-prefix allowlist via ExtensionLoader to restrict which classes can be initialized.

Affected products

Apache OpenNLP before 2.5.10, before 3.0.0-M5

Timeline

2026-07-24: advisory: CVE-2026-63317 published by Apache Software Foundation

References

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