CVE-2021-43980

LOW

Apache Tomcat < 8.5.77 - Race Condition

Title source: rule
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-43980. PoCs published by dbolkensteyn.

AI-analyzed exploit summary The repository contains only a generic GitLab README template and a CI configuration file, with no actual exploit code or technical details related to CVE-2021-43980.

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.

Exploits (1)

gitlab STUB
by dbolkensteyn · poc
https://gitlab.com/dbolkensteyn/cve-2021-43980

The repository contains only a generic GitLab README template and a CI configuration file, with no actual exploit code or technical details related to CVE-2021-43980.

Classification
Stub 95%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: unknown
No auth needed
devstral-2 · analyzed Feb 23, 2026 Full analysis →

References (4)

Core 4
Core References
Mailing List, Third Party Advisory mailing-list
http://www.openwall.com/lists/oss-security/2022/09/28/1
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2022/10/msg00029.html
Third Party Advisory vendor-advisory
https://www.debian.org/security/2022/dsa-5265

Scores

CVSS v3 3.7
EPSS 0.0020
EPSS Percentile 42.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-362
Status published
Products (5)
apache/tomcat 10.1.0 milestone1 (12 CPE variants)
apache/tomcat 8.5.0 - 8.5.77
debian/debian_linux 10.0
debian/debian_linux 11.0
org.apache.tomcat/tomcat 8.5.0 - 8.5.78Maven
Published Sep 28, 2022
Tracked Since Feb 18, 2026