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Fencer Intel
medium 4.3

CVE-2020-13943 json

Exposure of Sensitive Information to an Unauthorized Actor in Apache Tomcat

published 6y ago modified last mo. also BIT-tomcat-2020-13943 , EUVD-2022-0967 , GHSA-f268-65qc-98vg

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
52.6%
EPSS 52.6% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

If an HTTP/2 client connecting to Apache Tomcat 10.0.0-M1 to 10.0.0-M7, 9.0.0.M1 to 9.0.37 or 8.5.0 to 8.5.57 exceeded the agreed maximum number of concurrent streams for a connection (in violation of the HTTP/2 protocol), it was possible that a subsequent request made on that connection could contain HTTP headers - including HTTP/2 pseudo headers - from a previous request rather than the intended headers. This could lead to users seeing responses for unexpected resources.

Patch / fix

  • maven org.apache.tomcat:tomcat-coyote 8.5.58, 9.0.38, 10.0.0-M8
  • bitnami tomcat 8.5.1, 8.5.2, 8.5.3, 8.5.4, 8.5.5, 8.5.6, 8.5.7, 8.5.8, 8.5.9, 8.5.10, 8.5.11, 8.5.12, 8.5.13, 8.5.14, 8.5.15, 8.5.16, 8.5.17, 8.5.18, 8.5.19, 8.5.20, 8.5.21, 8.5.22, 8.5.23, 8.5.24, 8.5.25, 8.5.26, 8.5.27, 8.5.28, 8.5.29, 8.5.30, 8.5.31, 8.5.32, 8.5.33, 8.5.34, 8.5.35, 8.5.36, 8.5.37, 8.5.38, 8.5.39, 8.5.40, 8.5.41, 8.5.42, 8.5.43, 8.5.44, 8.5.45, 8.5.46, 8.5.47, 8.5.48, 8.5.49, 8.5.50, 8.5.51, 8.5.52, 8.5.53, 8.5.54, 8.5.55, 8.5.56, 8.5.57, 8.5.58, 9.0.38
  • tomcat9 Debian 14, Debian 13, Debian 12 9.0.38-1

debian advisories DEBIAN-CVE-2020-13943

  • jws5-tomcat jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el7jws
  • jws5-tomcat jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el8jws
  • jws5-tomcat-lib jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el7jws
  • jws5-tomcat-lib jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el8jws
  • jws5-tomcat-native jboss enterprise web server 5.4 1.2.25-3.redhat_3.el7jws
  • jws5-tomcat-native jboss enterprise web server 5.4 1.2.25-3.redhat_3.el8jws
  • jws5-tomcat-javadoc jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el7jws
  • jws5-tomcat-javadoc jboss enterprise web server 5.4 9.0.36-9.redhat_8.1.el8jws

red hat advisories RHSA-2021:0494

  • tomcat SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 9.0.36-3.74.1
  • tomcat SLE Module for Web and Scripting 15 SP1 9.0.36-4.47.3
  • tomcat SLE Module for Web and Scripting 15 SP2 9.0.36-3.12.3
  • tomcat SLES for SAP 12 SP5, SLES 12 SP5 9.0.36-3.50.1
  • 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-2021:0040-1SUSE-SU-2020:3069-1SUSE-SU-2020:3068-1SUSE-SU-2020:2996-1

  • tomcat openSUSE Tumbleweed 9.0.36-8.4
  • tomcat10 openSUSE Tumbleweed 10.1.14-1.1
  • tomcat openSUSE Leap 15.1 9.0.36-lp151.3.33.1
  • tomcat openSUSE Leap 15.2 9.0.36-lp152.2.10.1

opensuse advisories openSUSE-SU-2024:11468-1openSUSE-SU-2024:13441-1openSUSE-SU-2020:1842-1openSUSE-SU-2020:1799-1

Is CVE-2020-13943 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2020-13943 updated cvss 5.3

tomcat: Apache Tomcat HTTP/2 Request mix-up

  • Red Hat Enterprise Linux 5 tomcat5 Red Hat Enterprise Linux 6 tomcat6, tomcat6-lib, tomcat6-log4j, tomcat6-javadoc, tomcat6-webapps, tomcat6-el-2.1-api, +4 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 pki-servlet-engine, pki-servlet-4.0-api
    affected: no fix planned “Will not fix”
  • Red Hat JBoss Data Grid 6 jbossweb jbossweb Red Hat JBoss Data Virtualization 6 jbossweb jbossweb Red Hat JBoss Enterprise Application Platform 6 jbossweb jbossweb Red Hat JBoss Fuse 6 tomcat
    affected: no fix planned “Out of support scope”
  • Red Hat Fuse 7.10
    fixed: vendor fix RHSA-2021:5134
  • Red Hat JBoss Web Server 5
    fixed: vendor fix RHSA-2021:0495
  • Red Hat JBoss Web Server 5.4 for RHEL 7 Server jws5-tomcat 9.0.36-9.redhat_8.1.el7jws, jws5-tomcat-lib 9.0.36-9.redhat_8.1.el7jws, jws5-tomcat-native 1.2.25-3.redhat_3.el7jws, jws5-tomcat-javadoc 9.0.36-9.redhat_8.1.el7jws, jws5-tomcat-selinux 9.0.36-9.redhat_8.1.el7jws, jws5-tomcat-webapps 9.0.36-9.redhat_8.1.el7jws, +5 more Red Hat JBoss Web Server 5.4 for RHEL 8 jws5-tomcat 9.0.36-9.redhat_8.1.el8jws, jws5-tomcat-lib 9.0.36-9.redhat_8.1.el8jws, jws5-tomcat-native 1.2.25-3.redhat_3.el8jws, jws5-tomcat-javadoc 9.0.36-9.redhat_8.1.el8jws, jws5-tomcat-selinux 9.0.36-9.redhat_8.1.el8jws, jws5-tomcat-webapps 9.0.36-9.redhat_8.1.el8jws, +5 more
    fixed: vendor fix RHSA-2021:0494
  • Red Hat Support for Spring Boot 2.4.9
    fixed: vendor fix RHSA-2021:4012
  • Red Hat Decision Manager 7 tomcat 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 tomcat Red Hat OpenStack Platform 10 (Newton) opendaylight Red Hat OpenStack Platform 13 (Queens) opendaylight Red Hat Process Automation 7 tomcat
    +1 more products
    Red Hat Software Collections rh-java-common-tomcat-lib, rh-java-common-tomcat-javadoc, rh-java-common-tomcat-el-2.2-api, rh-java-common-tomcat-jsp-2.2-api, rh-java-common-tomcat-servlet-3.0-api
    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
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

52.64% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:P/I:N/A:N
OSV 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.apache.tomcat:tomcat-coyote
>=10.0.0-M1, <10.0.0-M8
>=9.0.0-M1, <9.0.38
>=8.5.0, <8.5.58
10.0.0-M8
9.0.38
8.5.58
bitnami tomcat
>=8.5.0, <8.5.1
>=8.5.1, <8.5.2
>=8.5.2, <8.5.3
>=8.5.3, <8.5.4
>=8.5.4, <8.5.5
>=8.5.5, <8.5.6
>=8.5.6, <8.5.7
>=8.5.7, <8.5.8
>=8.5.8, <8.5.9
>=8.5.9, <8.5.10
>=8.5.10, <8.5.11
>=8.5.11, <8.5.12
>=8.5.12, <8.5.13
>=8.5.13, <8.5.14
>=8.5.14, <8.5.15
>=8.5.15, <8.5.16
>=8.5.16, <8.5.17
>=8.5.17, <8.5.18
>=8.5.18, <8.5.19
>=8.5.19, <8.5.20
>=8.5.20, <8.5.21
>=8.5.21, <8.5.22
>=8.5.22, <8.5.23
>=8.5.23, <8.5.24
>=8.5.24, <8.5.25
>=8.5.25, <8.5.26
>=8.5.26, <8.5.27
>=8.5.27, <8.5.28
>=8.5.28, <8.5.29
>=8.5.29, <8.5.30
>=8.5.30, <8.5.31
>=8.5.31, <8.5.32
>=8.5.32, <8.5.33
>=8.5.33, <8.5.34
>=8.5.34, <8.5.35
>=8.5.35, <8.5.36
>=8.5.36, <8.5.37
>=8.5.37, <8.5.38
>=8.5.38, <8.5.39
>=8.5.39, <8.5.40
>=8.5.40, <8.5.41
>=8.5.41, <8.5.42
>=8.5.42, <8.5.43
>=8.5.43, <8.5.44
>=8.5.44, <8.5.45
>=8.5.45, <8.5.46
>=8.5.46, <8.5.47
>=8.5.47, <8.5.48
>=8.5.48, <8.5.49
>=8.5.49, <8.5.50
>=8.5.50, <8.5.51
>=8.5.51, <8.5.52
>=8.5.52, <8.5.53
>=8.5.53, <8.5.54
>=8.5.54, <8.5.55
>=8.5.55, <8.5.56
>=8.5.56, <8.5.57
>=8.5.57, <8.5.58
>=9.0.0, <9.0.38
8.5.1
8.5.2
8.5.3
8.5.4
8.5.5
8.5.6
8.5.7
8.5.8
8.5.9
8.5.10
8.5.11
8.5.12
8.5.13
8.5.14
8.5.15
8.5.16
8.5.17
8.5.18
8.5.19
8.5.20
8.5.21
8.5.22
8.5.23
8.5.24
8.5.25
8.5.26
8.5.27
8.5.28
8.5.29
8.5.30
8.5.31
8.5.32
8.5.33
8.5.34
8.5.35
8.5.36
8.5.37
8.5.38
8.5.39
8.5.40
8.5.41
8.5.42
8.5.43
8.5.44
8.5.45
8.5.46
8.5.47
8.5.48
8.5.49
8.5.50
8.5.51
8.5.52
8.5.53
8.5.54
8.5.55
8.5.56
8.5.57
8.5.58
9.0.38

Affected products

  • n/a Apache Tomcat

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Intel 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.