CVE-2026-76986
Received Received - Intake

XSS in Apache Wicket via Unescaped Default Option

Publication date: 2026-08-31

Last updated on: 2026-08-31

Assigner: Apache Software Foundation

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. This issue affects Apache Wicket: from 8.0.0 through 8.18.0, from 9.0.0 through 9.23.0, from 10.0.0 through 10.10.0. Older, unsupported releases from 1.5.0 onwards are also affected. Users are recommended to upgrade to version 8.19.0, 9.24.0 or 10.11.0, which fix the issue.

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Meta Information

Published
2026-08-31
Last Modified
2026-08-31
Generated
2026-08-31
AI Q&A
2026-08-31
EPSS Evaluated
N/A
NVD
CVE-2026-76986
EUVD
EUVD-2026-68517

Affected Vendors & Products

Showing 8 associated CPEs
Vendor Product Version / Range
apache wicket 1.5.0
apache wicket 8.19.0
apache wicket 9.24.0
apache wicket 10.11.0
apache wicket From 8.0.0 (inc) to 8.18.0 (inc)
apache wicket From 9.0.0 (inc) to 9.23.0 (inc)
apache wicket From 10.0.0 (inc) to 10.10.0 (inc)
apache wicket From 1.5.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability involves improper input neutralization in Apache Wicket, where the default option in dropdown menus is not properly escaped. This allows untrusted data to be rendered as-is in the web page, potentially leading to cross-site scripting (XSS) attacks if an attacker can influence the default option value.

Detection Guidance

Check Apache Wicket version with commands like 'mvn dependency:tree | grep wicket' or inspect WEB-INF/lib for wicket-core*.jar. Affected versions are 8.0.0-8.18.0, 9.0.0-9.23.0, 10.0.0-10.10.0, and older unsupported releases from 1.5.0.

Impact Analysis

An attacker could exploit this to inject malicious scripts into web pages, leading to unauthorized actions, data theft, or session hijacking. Users of affected applications may face compromised accounts or exposed sensitive information if the application uses custom logic for default dropdown options.

Compliance Impact

This vulnerability could lead to data breaches or unauthorized access, violating GDPR's data protection requirements and HIPAA's security rules. Organizations may face fines or penalties if such vulnerabilities are exploited due to inadequate input sanitization.

Mitigation Strategies

Upgrade Apache Wicket to version 8.19.0, 9.24.0, or 10.11.0. If upgrading is not possible, override getNullValidDisplayValue() or getNullKeyDisplayValue() to escape user-controlled input in custom implementations.

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