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

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-20 · updated 2026-10-20
Weakness: CWE-362

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 products

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

References

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

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