Cyber Resilience

CVE-2021-43980

Low

Published: 28 September 2022

Published
28 September 2022
Modified
21 May 2025
KEV Added
Patch
CVSS Score v3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0020 42.3th percentile
Risk Priority 8 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-43980 is a low-severity Race Condition (CWE-362) vulnerability in Apache Tomcat. Its CVSS base score is 3.7 (Low).

Operationally, ranked at the 42.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

apache
tomcat
10.1.0 · 8.5.0 — 8.5.77 · 9.0.0 — 9.0.60 · 10.0.0 — 10.0.18
debian
debian linux
10.0, 11.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-362

Accurate timestamps from internal clocks enable detection of race conditions by providing reliable event ordering in audit logs.

addresses: CWE-362

Coordination of concurrent security activities reduces the probability that shared resources will be accessed simultaneously without proper synchronization.

References