CVE-2026-86243 Apache CVE debrief

Who should care

Defenders and administrators of systems using Apache Tomcat Native should assess exposure and prioritize upgrading to version 1.3.9 or 2.0.16. This includes operators responsible for maintaining and securing systems that utilize Apache Tomcat Native, as well as vulnerability management and security teams who need to verify inventory and assess potential impacts on their platforms.

Why it matters

The buffer over-read vulnerability in Apache Tomcat Native during the TLS handshake permits a malicious user to trigger a DoS via a JVM crash. Defenders and administrators of systems using Apache Tomcat Native should assess exposure and prioritize upgrading to version 1.3.9 or 2.0.16.

• Potential DoS via JVM crash requires verification from official sources
• Upgrade to version 1.3.9 or 2.0.16 to fix the issue
• Verify inventory of Apache Tomcat Native installations

Technical summary

The buffer over-read vulnerability in Apache Tomcat Native during the TLS handshake allows a malicious user to trigger a DoS via a JVM crash. The issue affects Apache Tomcat Native versions 1.3.0 through 1.3.8 and 2.0.0 through 2.0.15. This vulnerability can be triggered by a malicious user, potentially leading to a denial of service (DoS) via a JVM crash. The affected versions of Apache Tomcat Native are 1.3.0 through 1.3.8 and 2.0.0 through 2.0.15. Users of these versions should take immediate action to mitigate the risk.

Defensive priority

Upgrade to version 1.3.9 or 2.0.16 to fix the issue. Assess exposure for systems using Apache Tomcat Native versions 1.3.0 through 1.3.8 and 2.0.0 through 2.0.15.

Recommended defensive actions

• Upgrade to version 1.3.9 or 2.0.16
• Assess exposure for systems using Apache Tomcat Native versions 1.3.0 through 1.3.8 and 2.0.0 through 2.0.15
• Verify inventory of Apache Tomcat Native installations
• 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 NVD vulnerability detail page provide information on the buffer over-read vulnerability in Apache Tomcat Native. The vendor advisory and mailing list references offer additional context.

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.