Critical Padding Oracle Vulnerability in Apache Tomcat Packages
Summary
DEBIAN-CVE-2026-29146: Padding Oracle vulnerability in Apache Tomcat's EncryptInterceptor with default configuration. Affects tomcat10 versions 10.1.10-1 – 10.1.9-1. No fix is published. How to fix ↓
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Background
Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, and Java Expression Language technologies. It is widely used for deploying Java applications and provides a robust environment for running web applications. The affected versions of Tomcat, including 7.0.x, 8.5.x, 9.0.x, 10.0.x, and 11.0.x, are vulnerable to a Padding Oracle attack when using the EncryptInterceptor with default configurations, which can lead to unauthorized access to sensitive data.
Vulnerability Detail
The vulnerability, identified as CVE-2026-29146, arises from a Padding Oracle issue in the EncryptInterceptor of Apache Tomcat. This flaw allows an attacker to exploit the way encrypted data is processed, potentially leading to decryption of sensitive information. The vulnerability affects multiple versions of Tomcat, specifically from 11.0.0-M1 to 11.0.18, 10.0.0-M1 to 10.1.52, 9.0.13 to 9.0.115, 8.5.38 to 8.5.100, and 7.0.100 to 7.0.109. If exploited, this vulnerability could result in significant data breaches and compromise the integrity of web applications.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
If immediate upgrading is not feasible, consider disabling the EncryptInterceptor or using a different encryption mechanism until the upgrade can be performed. This can be done by modifying the configuration files of Tomcat to exclude the EncryptInterceptor from the encryption process.
Conclusion
The Padding Oracle vulnerability in Apache Tomcat poses a serious risk to applications using affected versions. Users are strongly encouraged to upgrade to the latest patched versions to mitigate this risk. Additionally, utilizing tools like Vulert can help in monitoring for such vulnerabilities in real-time.
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FAQ
A Padding Oracle attack is a type of cryptographic attack that exploits the way padding is handled in encrypted messages. By observing the responses of a system to different inputs, an attacker can gain information about the plaintext.
The affected versions include Apache Tomcat from 11.0.0-M1 through 11.0.18, 10.0.0-M1 through 10.1.52, 9.0.13 through 9.0.115, 8.5.38 through 8.5.100, and 7.0.100 through 7.0.109.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. By uploading your manifest file, such as package-lock.json, you can check if your application is affected by this vulnerability.
If you cannot upgrade your Tomcat installation immediately, consider disabling the EncryptInterceptor or using an alternative encryption method until you can apply the necessary updates.
More information can be found in the official CVE database and on the Apache Tomcat security advisories page.
References
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