Vulnerability in Apache Software Foundation Apache Tomcat

[ Why it matters ]Priority signals

• Critical severity: CVSS 9.1

[ Description ]Official description

Incorrect object recycling and re-use vulnerability in Apache Tomcat affecting HTTP/2 processing of asynchronous servlets can trigger request and/or response mix-up between users. This issue affects Apache Tomcat: from 11.0.22 through 11.0.26, from 10.1.55 through 10.1.60, from 9.0.118 through 9.0.122. Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fixes the issue.

[ Fixes ]Fixes and patches

• Security bulletin: Apache Tomcat Apache_Tomcat_11.0.27Vendor patch or bulletin · CERT-FR · tomcat.apache.org/security-11.html, cited by CERT-FR CERTFR-2026-AVI-1358
• Security bulletin: Apache Tomcat Apache_Tomcat_10.1.61Vendor patch or bulletin · CERT-FR · tomcat.apache.org/security-10.html, cited by CERT-FR CERTFR-2026-AVI-1358
• Security bulletin: Apache Tomcat Apache_Tomcat_9.0.123Vendor patch or bulletin · CERT-FR · tomcat.apache.org/security-9.html, cited by CERT-FR CERTFR-2026-AVI-1358

[ Advisories ]Government CERT advisories

• CERT-FR21 Oct 2026CERTFR-2026-AVI-1358

  Multiple vulnerabilities in Apache Tomcat Translated from French

  Multiple vulnerabilities have been discovered in Apache Tomcat. Some of them allow an attacker to cause a breach of data confidentiality, a security policy bypass and a security problem not specified by the vendor.

  CVE-2026-65183CVE-2026-88041CVE-2026-80353+6 more CVEs
• BSI CERT-Bund20 Oct 2026WID-SEC-2026-4066

  Apache Tomcat: Multiple vulnerabilities Translated from German

  CVE-2026-101356CVE-2026-88041CVE-2026-80353+5 more CVEs

[ References ]References

• lists.apache.org/thread.html/d1xjt7bbjqw7y7n5mcb4fm815hpfgc27
• www.openwall.com/lists/oss-security/2026/10/20/27