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Fencer Vulns
low 3.7

CVE-2021-43980 json

Apache Tomcat: Information disclosure

published 2022-09-28 4 y ago modified 2026-09-08 2 mo ago also BIT-tomcat-2021-43980 , EUVD-2022-6865 , GHSA-jx7c-7mj5-9438

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven org.apache.tomcat:tomcat 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14
  • bitnami tomcat 8.5.78, 9.0.61, 10.0.19
  • tomcat9 Debian 14, Debian 13, Debian 12 9.0.62-1

debian advisories DEBIAN-CVE-2021-43980

  • jws5 jboss enterprise web server 5.7 1-8.el9jws
  • jws5-ecj jboss enterprise web server 5.7 4.20.0-1.redhat_00002.1.el7jws
  • jws5-ecj jboss enterprise web server 5.7 4.20.0-1.redhat_00002.1.el8jws
  • jws5-ecj jboss enterprise web server 5.7 4.20.0-1.redhat_00002.1.el9jws
  • jws5-tomcat jboss enterprise web server 5.7 9.0.62-9.redhat_00005.1.el7jws
  • jws5-tomcat jboss enterprise web server 5.7 9.0.62-9.redhat_00005.1.el8jws
  • jws5-tomcat jboss enterprise web server 5.7 9.0.62-9.redhat_00005.1.el9jws
  • jws5-runtime jboss enterprise web server 5.7 1-8.el9jws

red hat advisories RHSA-2022:7272

  • tomcat SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +3 more 9.0.36-150100.4.81.1
  • tomcat SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 9.0.36-150000.3.101.2
  • tomcat SLES for SAP 12 SP5, SLES 12 SP5 9.0.36-3.90.1
  • tomcat SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 9.0.115-3.160.1

suse advisories SUSE-SU-2026:1058-1SUSE-SU-2022:4257-1SUSE-SU-2022:4221-1SUSE-SU-2022:4009-1

  • tomcat openSUSE Tumbleweed 9.0.43-11.1
  • tomcat10 openSUSE Tumbleweed 10.1.14-1.1

opensuse advisories openSUSE-SU-2024:12534-1openSUSE-SU-2024:13441-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-43980 updated cvss 3.7

Tomcat: Information disclosure

  • Red Hat Enterprise Linux 8 pki-servlet-engine, pki-servlet-4.0-api Red Hat Enterprise Linux 9 pki-servlet-engine, pki-servlet-4.0-api
    affected: no fix available “Fix deferred”
  • Red Hat JWS 5.7.0
    fixed: vendor fix RHSA-2022:7273
  • Red Hat JBoss Web Server 5.7 for RHEL 7 Server jws5-ecj 4.20.0-1.redhat_00002.1.el7jws, jws5-tomcat 9.0.62-9.redhat_00005.1.el7jws, jws5-tomcat-native 1.2.31-10.redhat_10.el7jws, jws5-tomcat-lib 9.0.62-9.redhat_00005.1.el7jws, jws5-tomcat-javadoc 9.0.62-9.redhat_00005.1.el7jws, jws5-tomcat-selinux 9.0.62-9.redhat_00005.1.el7jws, +8 more Red Hat JBoss Web Server 5.7 for RHEL 8 jws5-ecj 4.20.0-1.redhat_00002.1.el8jws, jws5-tomcat 9.0.62-9.redhat_00005.1.el8jws, jws5-tomcat-native 1.2.31-10.redhat_10.el8jws, jws5-tomcat-lib 9.0.62-9.redhat_00005.1.el8jws, jws5-tomcat-javadoc 9.0.62-9.redhat_00005.1.el8jws, jws5-tomcat-selinux 9.0.62-9.redhat_00005.1.el8jws, +6 more Red Hat JBoss Web Server 5.7 for RHEL 9 jws5 1-8.el9jws, jws5-runtime 1-8.el9jws, jws5-ecj 4.20.0-1.redhat_00002.1.el9jws, jws5-tomcat 9.0.62-9.redhat_00005.1.el9jws, jws5-javapackages-tools 3.4.1-5.15.11.el9jws, jws5-python-javapackages 3.4.1-5.15.11.el9jws, +15 more
    fixed: vendor fix RHSA-2022:7272
  • Red Hat Enterprise Linux 6 tomcat6, tomcat6-lib, tomcat6-log4j, tomcat6-javadoc, tomcat6-webapps, tomcat6-el-2.1-api, +4 more Red Hat Enterprise Linux 7 tomcat, tomcat-lib, tomcat-jsvc, tomcat-javadoc, tomcat-webapps, tomcat-el-2.2-api, +4 more Red Hat JBoss Web Server 3 tomcat7 tomcat7, tomcat8 tomcat8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

2.36% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
OSV 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.apache.tomcat:tomcat
>=8.5.0, <8.5.78
>=9.0.0-M1, <9.0.62
>=10.0.0-M1, <10.0.20
>=10.1.0-M1, <10.1.0-M14
8.5.78
9.0.62
10.0.20
10.1.0-M14
bitnami tomcat
>=8.5.0, <8.5.78
>=9.0.0, <9.0.61
>=10.0.0, <10.0.19
8.5.78
9.0.61
10.0.19

Affected products

  • Apache Software Foundation Apache Tomcat

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.