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Vulnerability · Published Oct 20, 2026 · Assigned by apache

CVE-2026-101356Apache Tomcat: HTTP/2 request/response mix-up after error during async processing

Critical 9.1

In plain English

A critical-severity race condition in Apache Tomcat from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 57.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12tomcat10no fix listedDEBIAN-CVE-2026-101356
Debian:13tomcat10no fix listedDEBIAN-CVE-2026-101356
Debian:14tomcat10no fix listedDEBIAN-CVE-2026-101356
Debian:13tomcat11no fix listedDEBIAN-CVE-2026-101356
Debian:14tomcat11no fix listedDEBIAN-CVE-2026-101356
Debian:12tomcat99.0.70-2DEBIAN-CVE-2026-101356
Debian:13tomcat99.0.70-2DEBIAN-CVE-2026-101356
Debian:14tomcat99.0.70-2DEBIAN-CVE-2026-101356
Ubuntu:24.04:LTStomcat10no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.04:LTStomcat10no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.10tomcat10no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.04:LTStomcat11no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.10tomcat11no fix listedUBUNTU-CVE-2026-101356
Ubuntu:24.04:LTStomcat9no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.04:LTStomcat9no fix listedUBUNTU-CVE-2026-101356
Ubuntu:26.10tomcat9no fix listedUBUNTU-CVE-2026-101356

Affected products (as reported)

VendorProductVersions
Apache Software Foundation Apache Tomcat 11.0.22 – through 11.0.2610.1.55 – through 10.1.609.0.118 – through 9.0.122

Weakness: CWE-362 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

References