Description
Buffer under-read vulnerability in Apache Tomcat meant that a large non-blocking write could result in the response body being split between the current request and the next request received on that connection leading most likely to failure of the second request and possibly leakage of data from the first response to the second.
This issue affects Apache Tomcat: from 11.0.0-M25 through 11.0.26.
Users are recommended to upgrade to version 11.0.27, which fixes the issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache Tomcat | 11.0.0-M25 – ≤ 11.0.26 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | tomcat11 | No fix yet | — |
| Debian 13 | tomcat11 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | tomcat9 +2 | No fix yet | — |
| Ubuntu 26.04 LTS | tomcat9 +2 | No fix yet | — |
| Ubuntu 24.04 LTS | tomcat9 +1 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | tomcat9 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | tomcat9 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | tomcat8 +1 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | tomcat7 +1 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | tomcat6 +1 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | tomcat10 +9 | 10.1.61-0.1.hum1 | RHSA-2026:85926 |
| Red Hat Hardened Images 1 | tomcat11 +9 | 11.0.27-0.1.hum1 | RHSA-2026:81365 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | tomcat11 | 11.0.27-1.1 | openSUSE-SU-2026:12256-1 |
Advisories 4
- RHSA-2026:81365 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:85926 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-4066 Apache Tomcat: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
- openSUSE-SU-2026:12256-1 tomcat11-11.0.27-1.1 on GA media SUSE / openSUSE Security Updates · Oct 24, 2026