CVE-2026-63317: Software Security Vulnerability Vulnerability
MODERATECVE-2026-63317 is a MODERATE (CVSS 5.6) security vulnerability vulnerability (CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.. Remediation is available in the latest vendor maintenance releases.
CVE-2026-63317 at a Glance
Security Impact
CVSS: 5.6
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L).
How to Fix CVE-2026-63317
To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:treeHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-63317, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:treeAnalyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.
Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection'), where the product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
References
Frequently Asked Questions
What is CVE-2026-63317?
Which Software versions are affected?
What version fixes CVE-2026-63317?
What is the CVSS score of CVE-2026-63317?
What CWE is associated with CVE-2026-63317?
How can I check Maven dependencies for CVE-2026-63317?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-ccq5-x868-5p6x",
"modified" : "2026-07-24T21:32:21Z",
"published" : "2026-07-24T09:32:16Z",
"aliases" : [ "CVE-2026-63317" ],
"details" : "Arbitrary Class Instantiation via XML Feature Generator Descriptor and Format Name in Apache OpenNLP\n\nVersions Affected: \n\n- before 2.5.10\n- before 3.0.0-M5\n\nDescription: \n\nThree code paths in Apache OpenNLP load a class by its fully-qualified name via Class.forName() and invoke its no-arg constructor without any prior validation of the class name or its type. \n\nThe affected paths are: \n\n(1) GeneratorFactory, which reads the class attribute of generator elements in an XML feature generator descriptor; such descriptors are embedded as artifacts in model archives (e.g. TokenNameFinder and POSTagger models) and are parsed during model loading, so an attacker who can supply a crafted model archive controls the class name directly. \n\n(2) StreamFactoryRegistry.getFactory(Class, String), which falls back to interpreting an unregistered format name as the fully-qualified class name of an ObjectStreamFactory; this is exploitable in applications that pass untrusted format names (e.g. exposing the -format parameter of the command-line tooling to external input). \n\n(3) StringInterners, which instantiates the interner implementation named by the opennlp.interner.class system property; this value is normally deployer-controlled, so it is hardened as defense in depth rather than being independently attacker-reachable.\n\nExploitation requires a class with attacker-useful side effects in its static initializer or no-arg constructor (JNDI lookup, outbound network I/O, filesystem access) to be present on the classpath, so this is not drop-in remote code execution. T\n\nMitigation: \n\nUpgrade to a fixed release. \n\nThe fix routes all three paths through ExtensionLoader.instantiateExtension(...), which consults a package-prefix allowlist before Class.forName() is invoked, so a disallowed class is never loaded, initialized, or constructed. \nClasses under the opennlp. prefix remain permitted by default. Deployments that load models referencing feature generator factories, object stream factories, or string interners outside opennlp.* must opt those packages in, either programmatically via ExtensionLoader.registerAllowedPackage(String) before the first model load, or by setting the OPENNLP_EXT_ALLOWED_PACKAGES system property to a comma-separated list of allowed package prefixes. \n\nUsers who cannot upgrade immediately should ensure all model files and format names are sourced from trusted origins and should audit their classpath for classes with side-effecting static initializers or constructors.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-63317"
}, {
"type" : "WEB",
"url" : "https://lists.apache.org/thread/myr446n8t3gv8gq8wbpxm41olx16d8yj"
}, {
"type" : "WEB",
"url" : "http://www.openwall.com/lists/oss-security/2026/07/24/7"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-470" ],
"severity" : "MODERATE",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-07-24T09:16:25Z"
}
}