EncryptInterceptor fail-open bypass in Apache Tomcat Tribes clustering leading to unauthenticated RCE via Java deserialization.

Affected: 11.0.19+, 10.1.53+, 9.0.116+. Fixed in: 11.0.21, 10.1.54, 9.0.117.

Found and reported by Bartlomiej Dmitruk (striga.ai).

Writeup: https://striga.ai/research/tomcat-tribes-unauth-rce

• Docker
• Java 21
• Python 3

One-command reproduction:

bash run.sh

This builds the Docker image, starts Tomcat 11.0.20 with EncryptInterceptor, generates a CC6 gadget chain payload, sends it unencrypted to the Tribes receiver on port 4000, and verifies RCE by checking for /tmp/pwned inside the container.

docker rm -f tomcat-encrypt-poc