CVE-2026-82956 Apache Software Foundation CVE debrief

Who should care

Developers and administrators of Apache Wicket applications should assess their exposure and take action to upgrade to patched versions or implement additional security measures. This includes reviewing application code for usage of AjaxNewWindowNotifyingBehavior, implementing additional input validation and sanitization for user-supplied data, and monitoring for potential attacks. Security teams should prioritize patching affected systems and review their

Why it matters

CVE-2026-82956 is a high-severity vulnerability in Apache Wicket that can lead to XSS attacks. Developers and administrators should assess their exposure and take action to upgrade to patched versions or implement additional security measures.

• XSS attacks can lead to unauthorized access to sensitive data
• Attackers can inject malicious JavaScript code to steal user credentials or take control of user sessions
• The vulnerability can be exploited by an attacker with access to the affected application

Technical summary

The vulnerability is caused by the lack of input validation in the AjaxNewWindowNotifyingBehavior component. The component stores the value of the window.name property, which is supplied by the client, and uses it to generate JavaScript code without proper escaping. This can lead to XSS attacks when a page instance is rendered. The affected versions are Apache Wicket 8.0.0 through 8.19.0, 9.0.0 through 9.24.0, and 10.0.0 through 10.11.0. Users are recommended to upgrade to version 8.20.0, 9.25.0, or 10.12.0, which fix the issue. The vulnerability can be exploited by an attacker with access to the affected application, potentially leading to unauthorized access to sensitive data and injection of malicious Java

Defensive priority

Upgrade to patched versions

Recommended defensive actions

• Upgrade to Apache Wicket version 8.20.0, 9.25.0, or 10.12.0
• Review application code for usage of AjaxNewWindowNotifyingBehavior
• Implement additional input validation and sanitization for user-supplied data
• Confirm whether affected Apache Wicket product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability is caused by the lack of input validation in the AjaxNewWindowNotifyingBehavior component. The component stores the value of the window.name property, which is supplied by the client, and uses it to generate JavaScript code without proper escaping. This can lead to XSS attacks when a page instance is rendered.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.