CVE-2026-43515: Apache Tomcat Security Constraints Misapplication Vulnerability
Summary
CVE-2026-43515: Apache Tomcat - Security constraints not correctly applied. Affects org.apache.tomcat.embed:tomcat-embed-core across 3 version ranges.
< 9.0.118
>= 10.1.0-M1, < 10.1.55
>= 11.0.0-M1, < 11.0.22
Fixed in 9.0.118, 10.1.55 or 11.0.22, depending on the release line you run. How to fix ↓
Also tracked for
- tomcat · Bitnami
The same CVE-2026-43515 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, and Java Expression Language technologies. It provides a robust platform for running Java applications and is widely used for web server and application server purposes. The affected versions of Tomcat include 11.0.0-M1 to 11.0.21, 10.1.0-M1 to 10.1.54, and 9.0.0.M1 to 9.0.117, which may expose applications to security risks due to improper handling of security constraints.
Vulnerability Detail
The vulnerability arises from the misapplication of security constraints when multiple constraints define an HTTP method constraint for the same extension pattern. In such cases, only the first method constraint is applied, which can lead to unauthorized access or exposure of sensitive data. This issue is critical as it can allow attackers to bypass security measures, potentially compromising the integrity and confidentiality of the application.
How To Fix
Latest published version: 11.0.27 as of 23 Oct 2026
Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 9.0.1189.0.118 -
>= 10.1.0-M1, < 10.1.5510.1.55 -
>= 11.0.0-M1, < 11.0.2211.0.22
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
As a temporary workaround, users can review their security constraints and ensure that they are not relying on multiple constraints for the same extension pattern. However, this is not a substitute for upgrading to a secure version of Tomcat.
Conclusion
In summary, CVE-2026-43515 is a critical vulnerability in Apache Tomcat that affects multiple versions. Users are strongly advised to upgrade to the latest patched versions to mitigate the risk of unauthorized access and ensure the security of their applications.
See every vulnerability recorded for org.apache.tomcat.embed:tomcat-embed-core →
FAQ
CVE-2026-43515 is a vulnerability in Apache Tomcat that involves the misapplication of security constraints, potentially allowing unauthorized access.
Affected versions include Apache Tomcat 11.0.0-M1 to 11.0.21, 10.1.0-M1 to 10.1.54, and 9.0.0.M1 to 9.0.117.
The vulnerability can lead to unauthorized access to sensitive data and compromise the integrity of applications.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software using just the pom.xml file. Visit Vulert Scanner to check your application without signup.
The CVSS score of this vulnerability is 9.1, indicating a critical level of severity.
References
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