CVE-2026-66391 Apache Software Foundation CVE debrief

Who should care

Users of Apache Wicket versions from 9.0.0 through 9.23.0 and from 10.0.0 through 10.9.0 should be aware of this vulnerability and take action to upgrade to a fixed version. This includes operators, administrators, and security teams responsible for maintaining Apache Wicket deployments.

Technical summary

The vulnerability in Apache Wicket, tracked as CVE-2026-66391, is caused by the use of insufficiently random values and a protection mechanism failure. This could potentially allow attackers to exploit the vulnerability, impacting Apache Wicket deployments. The issue affects Apache Wicket versions from 9.0.0 through 9.23.0 and from 10.0.0 through 10.9.0. Users are recommended to upgrade to version 10.10.0, which fixes the issue. The CVSS score of 6.5 indicates a medium severity vulnerability. Evidence is limited to CVE and NVD details, and further verification is recommended. Operators, administrators, and security teams should review and update affected systems, monitor for potential exploitation attempts, and confirm whether affected product deployments exist in managed environments.

Defensive priority

Medium priority due to the CVSS score of 6.5 and the availability of a fix in version 10.10.0.

Recommended defensive actions

• Upgrade to Apache Wicket version 10.10.0 or later
• Review and update affected systems
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-07-27T17:16:41.750Z and last modified on 2026-07-27T20:26:26.840Z. The NVD entry is currently Awaiting Analysis. This vulnerability affects Apache Wicket versions from 9.0.0 through 9.23.0 and from 10.0.0 through 10.9.0. Users are recommended to upgrade to version 10.10.0, which fixes the issue. Evidence is limited to CVE and NVD details.

Official resources