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CVE-2021-30639

HIGHCVSS 7.5/10EPSS 6.89%

Last modified

CVE-2021-30639 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 6.89% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
6.89%

93.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
ApacheTomcat8.5.64
ApacheTomcat9.0.44
ApacheTomcat10.0.3
ApacheTomcat10.0.4
McafeeEpolicy Orchestrator< 5.10.0
McafeeEpolicy Orchestrator5.10.0
OracleBig Data Spatial And Graph< 23.1

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-30639?
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.
How severe is CVE-2021-30639?
CVE-2021-30639 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 6.89% probability of exploitation in the next 30 days.
How do I fix CVE-2021-30639?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST