CVE-2021-43980

Apache Tomcat: Information disclosure

State: Published
Severity: 3.7 Low
Published: Sep 28, 2022
Updated: May 21, 2025
Reserved: Nov 17, 2021

Description

The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.

Scores

CVSS	Score	Vector	Source
3.1	3.7 Low	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N	CISA-ADP

Weaknesses

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

Product	Versions
Apache TomcatApache Software Foundation	10.1.0-M1 to 10.1.0-M12Affected 10.0.0-M1 to 10.0.18Affected 9.0.0-M1 to 9.0.60Affected 8.5.0 to 8.5.77Affected

References

https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3
[oss-security] 20220928 CVE-2021-43980: Apache Tomcat: Information disclosuremailing-list
[debian-lts-announce] 20221026 [SECURITY] [DLA 3160-1] tomcat9 security updatemailing-list
DSA-5265vendor-advisory

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