CVE-2026-101356 Apache Software Foundation CVE debrief

Who should care

Apache Tomcat administrators, security teams, and users of affected versions should assess exposure and prioritize verification and remediation efforts. This includes reviewing compensating controls for exposed systems while remediation is scheduled and verified, and checking relevant monitoring, detection, and logs for exposed assets that need extra review.

Why it matters

Apache Tomcat users should assess exposure and prioritize verification due to an incorrect object recycling and re-use vulnerability affecting HTTP/2 processing of asynchronous servlets, which can trigger request and/or response mix-up between users.

• Potential request and/or response mix-up between users
• Verification of affected versions and patch application priority
• Monitoring for potential security incidents related to the vulnerability

Technical summary

The incorrect object recycling and re-use vulnerability in Apache Tomcat affects HTTP/2 processing of asynchronous servlets, potentially triggering request and/or response mix-up between users. Affected versions include 11.0.22 through 11.0.26, 10.1.55 through 10.1.60, and 9.0.118 through 9.0.122. Users are recommended to upgrade to version 11.0.27, 10.1.61, or 9.0.123. The vulnerability can lead to potential security incidents, including request and/or response mix-up between users. Apache Tomcat administrators and security teams should verify affected versions and apply patches or mitigations as needed.

Defensive priority

Apache Tomcat administrators and security teams should verify affected versions and apply patches or mitigations as needed.

Recommended defensive actions

• Verify Apache Tomcat version and assess exposure
• Apply patches or mitigations for affected versions
• Monitor for potential request and/or response mix-up between users
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, affected versions, and recommended upgrades. The vulnerability is caused by incorrect object recycling and re-use in Apache Tomcat's HTTP/2 processing of asynchronous servlets. This can trigger request and/or response mix-up between users. The affected versions are 11.0.22 through 11.0.26, 10.1.55 through 10.1.60, and 9.0.118 through 9.0.122. Users are recommended to upgrade to version 11.0.27, 10.1.61, or 9.0.123.

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.