CVE-2026-29146: Apache Tomcat: EncryptInterceptor vulnerable to padding oracle attack by default

[Mark Thomas <markt () apache org>]

Severity: important

Affected versions:

- Apache Tomcat 11.0.0-M1 through 11.0.18
- Apache Tomcat 10.0.0-M1 through 10.1.52
- Apache Tomcat 9.0.13 through 9.0.115
- Apache Tomcat 8.5.38 through 8.5.100
- Apache Tomcat 7.0.100 through 7.0.109

Description:

Padding Oracle vulnerability in Apache Tomcat's EncryptInterceptor with 
default configuration.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.18, from 
10.0.0-M1 through 10.1.52, from 9.0.13 through 9..115, from 8.5.38 
through 8.5.100, from 7.0.100 through 7.0.109.

Users are recommended to upgrade to version 11.0.19, 10.1.53 and 
9.0.116, which fixes the issue.

Credit:

Uri Katz and Avi Lumelsky (Oligo Security) (finder)

References:

https://lists.apache.org/thread/lzt04z2pb3dc5tk85obn80xygw3z1p0w
https://tomcat.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-29146