CVE-2026-55955: Apache Tomcat: EncryptInterceptor not protected against replay attacks

[Mark Thomas <markt () apache org>]

Severity: low

Affected versions:

- Apache Tomcat 11.0.0-M1 through 11.0.22
- Apache Tomcat 10.1.0-M1 through 10.1.55
- Apache Tomcat 9.0.13 through 9.0.118
- Apache Tomcat 8.5.38 through 8.5.100
- Apache Tomcat 7.0.100 through 7.0.109

Description:

Improper Authentication vulnerability in Apache Tomcat allowed a replay 
attack against the EncryptionInterceptor in the cluster component.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 
10.1.0-M1 through 10.1.55, from 9.0.13 through 9.0.18, from 8.5.38 
through 8.5.100, from 7.0.100 through 7.0.109.

Users are recommended to upgrade to version 11.0.23, 10.1.56, 9.0.119, 
which fixes the issue.

References:

https://lists.apache.org/thread/g4p5sf45p3f9r011pwqs9r54yd64s106
https://tomcat.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-55955