CVE-2021-30639

DoS after non-blocking IO error

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.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.40%
Vendor Advisory gentoo.org Vendor Advisory apache.org
Affected: Apache Software Foundation Apache Tomcat
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-30639?
CVE-2021-30639 has been scored as a high severity vulnerability.
How to fix CVE-2021-30639?
To fix CVE-2021-30639, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-30639 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-30639 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-30639?
CVE-2021-30639 affects Apache Software Foundation Apache Tomcat.
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