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Apache Tomcat Denial of Service vulnerability

High severity GitHub Reviewed Published Jun 15, 2020 to the GitHub Advisory Database • Updated Dec 8, 2023

Package

maven org.apache.tomcat.embed:tomcat-embed-core (Maven)

Affected versions

>= 9.0.0, < 9.0.16
>= 8.0.0, < 8.5.38

Patched versions

9.0.16
8.5.38

Description

The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.

References

Published by the National Vulnerability Database Apr 10, 2019
Reviewed Jun 15, 2020
Published to the GitHub Advisory Database Jun 15, 2020
Last updated Dec 8, 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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

72.665%
(98th percentile)

Weaknesses

CVE ID

CVE-2019-0199

GHSA ID

GHSA-qcxh-w3j9-58qr

Source code

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