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CVE-2021-30639

Severity

7.5

Description

A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.

Mitigation

We recommend upgrading to a version of this component that is not vulnerable to this specific issue.

Note: If this component is included as a bundled/transitive dependency of another component, there may not be an upgrade path. In this instance, we recommend contacting the maintainers who included the vulnerable package. Alternatively, we recommend investigating alternative components or a potential mitigating control.

Project

Apache Tomcat

Category
Denial of Service
Tags
data
Date Disclosed

2021-07-12

Date Discovered

2021-04-13

Apache Tomcat 10.0.x

First release:
2021-02-02
0
Support Lifecycle:
Namespace:
jakarta

Apache Tomcat 9.0.x

First release:
2018-01-18
0
Support Lifecycle:
Namespace:
javax

Apache Tomcat 8.5.x

First release:
2016-06-13
0
Support Lifecycle:
Namespace:
javax
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