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Concurrent Execution using Shared Resource with Improper Synchronization in Apache Tomcat

High severity GitHub Reviewed Published May 14, 2022 to the GitHub Advisory Database • Updated Feb 22, 2024

Package

maven org.apache.tomcat:tomcat (Maven)

Affected versions

>= 9.0.0.M1, <= 9.0.0.M13
>= 8.5.0, <= 8.5.8
>= 8.0.0RC1, < 8.0.41
>= 7.0.0, < 7.0.75
>= 6.0.16, < 6.0.50

Patched versions

9.0.0.M14
8.5.9
8.0.41
7.0.75
6.0.50

Description

A bug in the error handling of the send file code for the NIO HTTP connector in Apache Tomcat 9.0.0.M1 to 9.0.0.M13, 8.5.0 to 8.5.8, 8.0.0.RC1 to 8.0.39, 7.0.0 to 7.0.73 and 6.0.16 to 6.0.48 resulted in the current Processor object being added to the Processor cache multiple times. This in turn meant that the same Processor could be used for concurrent requests. Sharing a Processor can result in information leakage between requests including, not not limited to, session ID and the response body. The bug was first noticed in 8.5.x onwards where it appears the refactoring of the Connector code for 8.5.x onwards made it more likely that the bug was observed. Initially it was thought that the 8.5.x refactoring introduced the bug but further investigation has shown that the bug is present in all currently supported Tomcat versions.

References

Published by the National Vulnerability Database Aug 10, 2017
Published to the GitHub Advisory Database May 14, 2022
Reviewed Jul 6, 2022
Last updated Feb 22, 2024

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
High
Integrity
None
Availability
None

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:H/I:N/A:N

EPSS score

0.648%
(80th percentile)

Weaknesses

CVE ID

CVE-2016-8745

GHSA ID

GHSA-w3j5-q8f2-3cqq

Source code

Credits

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