CVE-2026-88041 Apache Software Foundation CVE debrief

Who should care

Defenders and administrators responsible for Apache Tomcat deployments should assess exposure and prioritize remediation to prevent potential information leakage between requests. This includes verifying current Apache Tomcat versions and implementing compensating controls until remediation can be applied. Security teams and vulnerability management teams should track exceptions and retest remediated assets.

Why it matters

Apache Tomcat users should assess exposure and prioritize remediation due to an incomplete cleanup vulnerability allowing trailer information leakage between requests.

• Potential information leakage between requests due to incomplete cleanup of trailer headers.
• Need for verification of current Apache Tomcat versions and exposure assessment.
• Priority for upgrading to fixed versions (11.0.27, 10.1.61, or 9.0.123) to prevent vulnerability exploitation.
• Monitoring for suspicious request patterns as a compensating control until remediation can be applied.

Technical summary

The incomplete cleanup vulnerability in Apache Tomcat allows trailer information from a previous request to leak into a subsequent request, affecting versions 11.0.0-M23 through 11.0.26, 10.1.27 through 10.1.60, and 9.0.92 through 9.0.122. This issue can lead to potential information leakage between requests. Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fix the issue. Defenders should verify current Apache Tomcat versions and assess exposure to prioritize remediation efforts and prevent vulnerability exploitation.

Defensive priority

Medium

Recommended defensive actions

• Assess exposure by reviewing current Apache Tomcat versions (11.0.0-M23 through 11.0.26, 10.1.27 through 10.1.60, 9.0.92 through 9.0.122) and prioritize upgrades to 11.0.27, 10.1.61, or 9.0.123.
• Verify inventory of Apache Tomcat deployments to identify potentially affected systems.
• Implement compensating controls, such as monitoring for suspicious request patterns, until remediation can be applied.
• Review 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.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The CVE record and source item provide details on the vulnerability, affected versions, and recommended upgrades. Evidence is limited to CVE Program and NVD records, which indicate an incomplete cleanup vulnerability in Apache Tomcat. Affected versions include 11.0.0-M23 through 11.0.26, 10.1.27 through 10.1.60, and 9.0.92 through 9.0.122. Defenders should verify current Apache Tomcat versions and assess exposure.

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.