Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-43980

19
FAUCET Score

CVE-2021-43980 is a concurrency bug in Apache Tomcat versions 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, including affected Debian packages. This flaw, rated with a CVSS score of 3.7 (LOW), could lead to client connections sharing an Http11Processor instance, causing responses to be sent to the wrong client. While the attack vector is network-based, the attack complexity is high, and the potential impact is limited to information disclosure (CWE-362). There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
>= 8.5.0, <= 8.5.77CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
>= 9.0.0, <= 9.0.60CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
>= 10.0.0, <= 10.0.18CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
10.1.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:10.1.0:milestone1:*:*:*:*:*:*
10.1.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:10.1.0:milestone10:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

3.7LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.91%
Probability of exploitation in next 30 days
EPSS Percentile
77.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0191 is in the 70th percentile among its peer group of 1,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.3 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (21)

mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 8.5.78
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 9.0.62
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 10.0.20
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 10.1.0-M14
redhatpatch availablevia redhat_api
Product: JWS 5.7.0
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 7Fixed in: jws5-ecj-0:4.20.0-1.redhat_00002.1.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 7Fixed in: jws5-tomcat-0:9.0.62-9.redhat_00005.1.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 7Fixed in: jws5-tomcat-native-0:1.2.31-10.redhat_10.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 8Fixed in: jws5-ecj-0:4.20.0-1.redhat_00002.1.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 8Fixed in: jws5-tomcat-0:9.0.62-9.redhat_00005.1.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 8Fixed in: jws5-tomcat-native-0:1.2.31-10.redhat_10.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-0:1-8.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-ecj-0:4.20.0-1.redhat_00002.1.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-javapackages-tools-0:3.4.1-5.15.11.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-jboss-logging-0:3.4.1-1.Final_redhat_00001.1.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-mod_cluster-0:1.4.3-2.Final_redhat_00002.1.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-tomcat-0:9.0.62-9.redhat_00005.1.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-tomcat-native-0:1.2.31-10.redhat_10.el9jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.7 on RHEL 9Fixed in: jws5-tomcat-vault-0:1.1.8-4.Final_redhat_00004.1.el9jws
View patch
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: pki-deps:10.6/pki-servlet-engine
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: pki-servlet-engine

Vendor Advisories (2)

mavenGHSA-jx7c-7mj5-9438low

Apache Tomcat Race Condition vulnerability

Sep 29, 2022
redhatCVE-2021-43980Low

Tomcat: Information disclosure

Sep 28, 2022

References

lists.apache.org / thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3
Mailing ListVendor Advisory
lists.debian.org / debian-lts-announce/2022/10/msg00029.html
Mailing ListThird Party Advisory
debian.org / security/2022/dsa-5265
Third Party Advisory
openwall.com / lists/oss-security/2022/09/28/1
Mailing ListThird Party Advisory