CVE-2026-76986

Technical Description

Improper neutralization of input during web page generation in Apache Wicket.

org.apache.wicket.markup.html.form.AbstractSingleSelectChoice, the base class of DropDownChoice, writes the body of the default option — the entry shown when no choice is selected — into the markup as it is, while every other option body in the same select is escaped according to the escape-model-strings setting. The body comes from getNullValidDisplayValue() or getNullKeyDisplayValue(), both of which are protected, so what they return is not necessarily the plain text the default implementation reads from a resource bundle.

An application is affected where it overrides one of those methods and returns a value holding data an attacker can influence, or where its own nullValid or null bundle entry holds such a value. The bundles shipped with Wicket contain plain text. RadioChoice overrides getDefaultChoice to emit no default option and is not affected.

As a workaround, escape the value in the override.

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Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References