CVE-2021-30639

DoS after non-blocking IO error

Published Jul 12, 2021 CVSS 3.1 · 7.5 High EPSS 6.9% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2021-1554 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.
Github GHSA Github GHSA GHSA-44qp-qhfv-c7f6 Improper Handling of Exceptional Conditions in Apache Tomcat
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Aug 3, 2024, 10:40 PM
Reserved
Apr 13, 2021, 12:00 AM
Status
Modified
Published
Jul 12, 2021, 3:15 PM
Modified
Jun 17, 2026, 3:50 AM
Severity
Important
Public date
Jul 12, 2021, 12:00 AM