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Fencer Intel
high 7.5

CVE-2021-25122 in the critical feed json

Apache Tomcat h2c request mix-up

published 5y ago modified last mo. also BIT-tomcat-2021-25122 , EUVD-2021-1340 , GHSA-j39c-c8hj-x4j3

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
18.1%
EPSS 18.1% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

Patch / fix

  • maven org.apache.tomcat.embed:tomcat-embed-core 8.5.63, 9.0.43, 10.0.2
  • maven org.apache.tomcat:tomcat-coyote 10.0.2
  • bitnami tomcat 8.5.62, 9.0.42, 10.0.1
  • Apache Software Foundation Apache Tomcat 8.5.62, 9.0.42, 10.0.2
  • tomcat9 Debian 14, Debian 13, Debian 12 9.0.43-1

debian advisories DEBIAN-CVE-2021-25122

  • tomcat9 Ubuntu 18.04 LTS 9.0.16-3ubuntu0.18.04.2
  • tomcat9 Ubuntu 20.04 LTS 9.0.31-1ubuntu0.2
  • tomcat8 Ubuntu Pro 18.04 LTS 8.5.39-1ubuntu1~18.04.3+esm2

ubuntu advisories UBUNTU-CVE-2021-25122

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • jws5-ecj jboss enterprise web server 5.5 4.12.0-3.redhat_2.2.el7jws
  • jws5-ecj jboss enterprise web server 5.5 4.12.0-3.redhat_2.2.el8jws
  • jws5-tomcat jboss enterprise web server 5.5 9.0.43-11.redhat_00011.1.el7jws
  • jws5-tomcat jboss enterprise web server 5.5 9.0.43-11.redhat_00011.1.el8jws
  • jws5-tomcat-lib jboss enterprise web server 5.5 9.0.43-11.redhat_00011.1.el7jws
  • jws5-tomcat-lib jboss enterprise web server 5.5 9.0.43-11.redhat_00011.1.el8jws
  • jws5-mod_cluster jboss enterprise web server 5.5 1.4.3-2.Final_redhat_00002.1.el7jws
  • jws5-mod_cluster jboss enterprise web server 5.5 1.4.3-2.Final_redhat_00002.1.el8jws

red hat advisories RHSA-2021:2561

  • tomcat SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 9.0.36-4.58.1
  • tomcat SLE Module for Web and Scripting 15 SP2 9.0.36-3.24.1
  • tomcat SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 9.0.36-3.79.1
  • tomcat SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +3 more 9.0.36-3.64.1
  • 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-2021:1009-1SUSE-SU-2021:1008-1SUSE-SU-2021:0989-1SUSE-SU-2021:0988-1

  • tomcat openSUSE Tumbleweed 9.0.36-8.4
  • tomcat10 openSUSE Tumbleweed 10.1.14-1.1
  • tomcat openSUSE Leap 15.2 9.0.36-lp152.2.22.1

opensuse advisories openSUSE-SU-2024:11468-1openSUSE-SU-2024:13441-1openSUSE-SU-2021:0496-1

Is CVE-2021-25122 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.

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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-2021-25122 updated cvss 7.5

tomcat: Request mix-up with h2c

  • Red Hat Enterprise Linux 8 pki-servlet-engine, pki-servlet-4.0-api
    affected: no fix available “Fix deferred”
  • 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 Red Hat OpenStack Platform 10 (Newton) opendaylight
    affected: no fix planned “Out of support scope”
  • Red Hat OpenStack Platform 13 (Queens) opendaylight
    affected: no fix planned “Will not fix”
  • Red Hat Fuse 7.11
    fixed: vendor fix RHSA-2022:5532
  • Red Hat JBoss Web Server 5
    fixed: vendor fix RHSA-2021:2562
  • Red Hat JBoss Web Server 5.5 for RHEL 7 Server jws5-ecj 4.12.0-3.redhat_2.2.el7jws, jws5-tomcat 9.0.43-11.redhat_00011.1.el7jws, jws5-tomcat-native 1.2.26-3.redhat_3.el7jws, jws5-tomcat-lib 9.0.43-11.redhat_00011.1.el7jws, jws5-tomcat-javadoc 9.0.43-11.redhat_00011.1.el7jws, jws5-tomcat-selinux 9.0.43-11.redhat_00011.1.el7jws, +12 more Red Hat JBoss Web Server 5.5 for RHEL 8 jws5-ecj 4.12.0-3.redhat_2.2.el8jws, jws5-tomcat 9.0.43-11.redhat_00011.1.el8jws, jws5-tomcat-native 1.2.26-3.redhat_3.el8jws, jws5-tomcat-lib 9.0.43-11.redhat_00011.1.el8jws, jws5-tomcat-javadoc 9.0.43-11.redhat_00011.1.el8jws, jws5-tomcat-selinux 9.0.43-11.redhat_00011.1.el8jws, +10 more
    fixed: vendor fix RHSA-2021:2561
  • Red Hat support for Spring Boot 2.3.10
    fixed: vendor fix RHSA-2021:3425
  • Red Hat Decision Manager 7 tomcat 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 tomcat Red Hat Process Automation 7 tomcat
    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

18.11% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.apache.tomcat.embed:tomcat-embed-core
>=10.0.0-M1, <10.0.2
>=9.0.0-M1, <9.0.43
>=8.5.0, <8.5.63
10.0.2
9.0.43
8.5.63
maven org.apache.tomcat:tomcat-coyote
>=10.0.0-M1, <10.0.2
10.0.2
bitnami tomcat
>=8.5.0, <8.5.62
>=9.0.0, <9.0.42
>=10.0.0, <10.0.1
8.5.62
9.0.42
10.0.1

Affected products

  • Apache Software Foundation Apache Tomcat

Classification

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

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.