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.
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
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | tomcat10 | no fix listed | DEBIAN-CVE-2026-101356 |
| Debian:13 | tomcat10 | no fix listed | DEBIAN-CVE-2026-101356 |
| Debian:14 | tomcat10 | no fix listed | DEBIAN-CVE-2026-101356 |
| Debian:13 | tomcat11 | no fix listed | DEBIAN-CVE-2026-101356 |
| Debian:14 | tomcat11 | no fix listed | DEBIAN-CVE-2026-101356 |
| Debian:12 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-101356 |
| Debian:13 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-101356 |
| Debian:14 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-101356 |
| Ubuntu:24.04:LTS | tomcat10 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.04:LTS | tomcat10 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.10 | tomcat10 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.04:LTS | tomcat11 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.10 | tomcat11 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:24.04:LTS | tomcat9 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.04:LTS | tomcat9 | no fix listed | UBUNTU-CVE-2026-101356 |
| Ubuntu:26.10 | tomcat9 | no fix listed | UBUNTU-CVE-2026-101356 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| 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