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Improper Handling of Exceptional Conditions in Apache Tomcat

High severity GitHub Reviewed Published Aug 13, 2021 to the GitHub Advisory Database • Updated Feb 3, 2023

Package

maven org.apache.tomcat:tomcat (Maven)

Affected versions

>= 10.0.3, < 10.0.5
>= 9.0.0, < 9.0.45
< 8.5.65

Patched versions

10.0.5
9.0.45
8.5.65

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.

References

Published by the National Vulnerability Database Jul 12, 2021
Reviewed Jul 13, 2021
Published to the GitHub Advisory Database Aug 13, 2021
Last updated Feb 3, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

1.321%
(86th percentile)

Weaknesses

CVE ID

CVE-2021-30639

GHSA ID

GHSA-44qp-qhfv-c7f6

Source code

No known source code
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