`CVE-2021-25122` Apache Tomcat

Affected software	Apache Tomcat
Severity	7.5 High CVSS 3.1 2 scores
Fixed in	`10.0.2`, `9.0.43`, `8.5.63`
Weakness	Information exposure (CWE-200)
Published	1 Mar 2021
Updated	8 Oct 2026

Description

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.

Exploitation status

No public exploit

No exploit has been reported in the sources we check. Published 5 years ago.

CISA KEV not listed
VulnCheck KEV not listed
CISA Vulnrichment exploitation: none
Indexed PoC none indexed
EPSS 18% chance in 30 days A model's forecast, not a report of exploitation. Higher than 97% of all scored CVEs.

Waratek protection

Protected by Waratek

Waratek has a rule that blocks attacks on this vulnerability.

Protection full
Action available patch rule
Review human ARMR file
Record active

Decided by	An ARMR patch file on disk for this CVE
Finding	CVE has an ARMR patch rule that provides mitigation

Decided by

An ARMR patch file on disk for this CVE

Finding

CVE has an ARMR patch rule that provides mitigation

ARMR rule files

1 file

The rule files Waratek ships for this CVE. Some CVEs need more than one, for example one per affected library or one per ARMR version.

CVE-2021-25122.armr patch rule, ARMR 2.6 added 2021-11-23 updated 2026-03-04

How to mitigate CVE-2021-25122

Upgrade Apache Tomcat to a release that fixes it: 10.0.2, 9.0.43 or 8.5.63. Until you can, Waratek RASP blocks exploitation with a rule written for this CVE. It runs inside the Java application, with no code changes.

Waratek RASP Runtime protection for Java applications

CVSS

7.5 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

Version Score Band Vector Assigner Type

CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N NVD Primary published

CVSS 2.0 5.0 none AV:N/AC:L/Au:N/C:P/I:N/A:N NVD Primary

Version	Score	Band	Vector	Assigner	Type
CVSS 3.1	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`	NVD	Primary	published
CVSS 2.0	5.0	none	`AV:N/AC:L/Au:N/C:P/I:N/A:N`	NVD	Primary

Affected software and releases

Oracle advisories

Advisory	Type	Quarter	Products Oracle names in its risk matrix
Oracle Critical Patch Update April 2025 ↗	CPU	2025-Q2	Oracle Autonomous Health Framework / Trace File Analyzer (Apache Tomcat) (23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0)
Oracle Critical Patch Update January 2022 ↗	CPU	2022-Q1	Oracle Communications / SEPP (Apache Tomcat) (1.6.0) Oracle Communications Applications / DBPlugin (Apache Tomcat) (10.0.1.5.0)
Oracle Critical Patch Update October 2021 ↗	CPU	2021-Q4	Oracle Database Server / Oracle Database Enterprise Edition (Apache Tomcat) (12.2.0.1, 19c, 21c) Oracle Graph Server and Client / Packaging/install (Apache Tomcat) (Prior to 21.3.0) Oracle Siebel CRM / EAI (Apache Tomcat) (21.9 and prior)
Oracle Critical Patch Update July 2021 ↗	CPU	2021-Q3	Oracle Construction and Engineering / HTTP Server (Apache Tomcat) (17.1, 17.2, 17.3) Oracle Fusion Middleware / MFT Runtime Server (Apache Tomcat) (12.2.1.3.0, 12.2.1.4.0) Oracle MySQL / Monitoring: General (Apache Tomcat) (8.0.23 and prior)

Advisory

Type

Quarter

Products Oracle names in its risk matrix

Oracle Critical Patch Update April 2025 ↗

CPU

2025-Q2

Oracle Autonomous Health Framework / Trace File Analyzer (Apache Tomcat) (23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0)

Oracle Critical Patch Update January 2022 ↗

CPU

2022-Q1

Oracle Communications / SEPP (Apache Tomcat) (1.6.0)
Oracle Communications Applications / DBPlugin (Apache Tomcat) (10.0.1.5.0)

Oracle Critical Patch Update October 2021 ↗

CPU

2021-Q4

Oracle Database Server / Oracle Database Enterprise Edition (Apache Tomcat) (12.2.0.1, 19c, 21c)
Oracle Graph Server and Client / Packaging/install (Apache Tomcat) (Prior to 21.3.0)
Oracle Siebel CRM / EAI (Apache Tomcat) (21.9 and prior)

Oracle Critical Patch Update July 2021 ↗

CPU

2021-Q3

Oracle Construction and Engineering / HTTP Server (Apache Tomcat) (17.1, 17.2, 17.3)
Oracle Fusion Middleware / MFT Runtime Server (Apache Tomcat) (12.2.1.3.0, 12.2.1.4.0)
Oracle MySQL / Monitoring: General (Apache Tomcat) (8.0.23 and prior)

Oracle components and versions

Family	Component	Versions, as Oracle lists them	Read as
Oracle Autonomous Health Framework	Trace File Analyzer (Apache Tomcat)	23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0	25.1.0 · 25.2.0
Oracle Communications	SEPP (Apache Tomcat)	1.6.0	1.6.0
Oracle Communications Applications	DBPlugin (Apache Tomcat)	10.0.1.5.0	10.0.1.5.0
Oracle Construction and Engineering	HTTP Server (Apache Tomcat)	17.1, 17.2, 17.3	17.1 · 17.2 · 17.3
Oracle Database Server	Oracle Database Enterprise Edition (Apache Tomcat)	12.2.0.1, 19c, 21c	12.2.0.1 · 19 · 21
Oracle Fusion Middleware	MFT Runtime Server (Apache Tomcat)	12.2.1.3.0, 12.2.1.4.0	12.2.1.3.0 · 12.2.1.4.0
Oracle Graph Server and Client	Packaging/install (Apache Tomcat)	Prior to 21.3.0
Oracle MySQL	Monitoring: General (Apache Tomcat)	8.0.23 and prior
Oracle Siebel CRM	EAI (Apache Tomcat)	21.9 and prior

Family

Component

Versions, as Oracle lists them

Read as

Oracle Autonomous Health Framework

Trace File Analyzer (Apache Tomcat)

23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0

25.1.0 · 25.2.0

Oracle Communications

SEPP (Apache Tomcat)

1.6.0

Oracle Communications Applications

DBPlugin (Apache Tomcat)

10.0.1.5.0

Oracle Construction and Engineering

HTTP Server (Apache Tomcat)

17.1, 17.2, 17.3

17.1 · 17.2 · 17.3

Oracle Database Server

Oracle Database Enterprise Edition (Apache Tomcat)

12.2.0.1, 19c, 21c

12.2.0.1 · 19 · 21

Oracle Fusion Middleware

MFT Runtime Server (Apache Tomcat)

12.2.1.3.0, 12.2.1.4.0

12.2.1.3.0 · 12.2.1.4.0

Oracle Graph Server and Client

Packaging/install (Apache Tomcat)

Prior to 21.3.0

Oracle MySQL

Monitoring: General (Apache Tomcat)

8.0.23 and prior

Oracle Siebel CRM

EAI (Apache Tomcat)

21.9 and prior

Maven packages

Affected and fixed versions, from OSV.dev

Package Introduced Fixed Last affected

org.apache.tomcat.embed:tomcat-embed-core 10.0.0-M1 10.0.2 unbounded

org.apache.tomcat.embed:tomcat-embed-core 9.0.0-M1 9.0.43 unbounded

org.apache.tomcat.embed:tomcat-embed-core 8.5.0 8.5.63 unbounded

org.apache.tomcat:tomcat-coyote 10.0.0-M1 10.0.2 unbounded

Package	Introduced	Fixed	Last affected
`org.apache.tomcat.embed:tomcat-embed-core`	10.0.0-M1	`10.0.2`	unbounded
`org.apache.tomcat.embed:tomcat-embed-core`	9.0.0-M1	`9.0.43`	unbounded
`org.apache.tomcat.embed:tomcat-embed-core`	8.5.0	`8.5.63`	unbounded
`org.apache.tomcat:tomcat-coyote`	10.0.0-M1	`10.0.2`	unbounded

Products and versions

14 products, 59 version entries

Source	Vendor	Product	Scheme	Affected versions
nvd	apache	tomcat	generic	≥ 8.5.0 and ≤ 8.5.61 · 9.0.0:milestone1 · 9.0.0:milestone10 · 9.0.0:milestone11 · 9.0.0:milestone12 · 9.0.0:milestone13 · 9.0.0:milestone14 · 9.0.0:milestone15 · 9.0.0:milestone16 · 9.0.0:milestone17 · 9.0.0:milestone18 · 9.0.0:milestone19 · 9.0.0:milestone2 · 9.0.0:milestone20 · 9.0.0:milestone21 · 9.0.0:milestone22 · 9.0.0:milestone23 · 9.0.0:milestone24 · 9.0.0:milestone25 · 9.0.0:milestone26 · 9.0.0:milestone27 · 9.0.0:milestone3 · 9.0.0:milestone4 · 9.0.0:milestone5 · ≥ 9.0.0 and ≤ 9.0.41 · 10.0.0 · 10.0.0:milestone1 · 10.0.0:milestone10 · 10.0.0:milestone2 · 10.0.0:milestone3 · 10.0.0:milestone4 · 10.0.0:milestone5 · 10.0.0:milestone6 · 10.0.0:milestone7 · 10.0.0:milestone8 · 10.0.0:milestone9
nvd	debian	debian linux	generic	9.0 · 10.0
nvd	oracle	agile product lifecycle management	generic	9.3.3 · 9.3.6
nvd	oracle	communications cloud native core policy	generic	1.14.0
nvd	oracle	communications cloud native core security edge protection proxy	generic	1.6.0
nvd	oracle	communications instant messaging server	generic	10.0.1.5.0
nvd	oracle	database	generic	12.2.0.1 · 19c · 21c
nvd	oracle	graph server and client	generic	21.3.0 · ＜ 21.3.0
nvd	oracle	instantis enterprisetrack	generic	17.1 · 17.2 · 17.3
nvd	oracle	managed file transfer	generic	12.2.1.3.0 · 12.2.1.4.0
nvd	oracle	mysql enterprise monitor	generic	≤ 8.0.23
nvd	oracle	siebel ui framework	generic	≤ 21.9
osv	org.apache.tomcat	tomcat-coyote	generic	≥ 10.0.0 and ＜ 10.0.2
osv	org.apache.tomcat.embed	tomcat-embed-core	generic	≥ 8.5.0 and ＜ 8.5.63 · ≥ 9.0.0 and ＜ 9.0.43 · ≥ 10.0.0 and ＜ 10.0.2

Source

Vendor

Product

Scheme

Affected versions

nvd

apache

tomcat

generic

≥ 8.5.0 and ≤ 8.5.61 · 9.0.0:milestone1 · 9.0.0:milestone10 · 9.0.0:milestone11 · 9.0.0:milestone12 · 9.0.0:milestone13 · 9.0.0:milestone14 · 9.0.0:milestone15 · 9.0.0:milestone16 · 9.0.0:milestone17 · 9.0.0:milestone18 · 9.0.0:milestone19 · 9.0.0:milestone2 · 9.0.0:milestone20 · 9.0.0:milestone21 · 9.0.0:milestone22 · 9.0.0:milestone23 · 9.0.0:milestone24 · 9.0.0:milestone25 · 9.0.0:milestone26 · 9.0.0:milestone27 · 9.0.0:milestone3 · 9.0.0:milestone4 · 9.0.0:milestone5 · ≥ 9.0.0 and ≤ 9.0.41 · 10.0.0 · 10.0.0:milestone1 · 10.0.0:milestone10 · 10.0.0:milestone2 · 10.0.0:milestone3 · 10.0.0:milestone4 · 10.0.0:milestone5 · 10.0.0:milestone6 · 10.0.0:milestone7 · 10.0.0:milestone8 · 10.0.0:milestone9

nvd

debian

debian linux

generic

9.0 · 10.0

nvd

oracle

agile product lifecycle management

generic

9.3.3 · 9.3.6

nvd

oracle

communications cloud native core policy

generic

1.14.0

nvd

oracle

communications cloud native core security edge protection proxy

generic

1.6.0

nvd

oracle

communications instant messaging server

generic

10.0.1.5.0

nvd

oracle

database

generic

12.2.0.1 · 19c · 21c

nvd

oracle

graph server and client

generic

21.3.0 · ＜ 21.3.0

nvd

oracle

instantis enterprisetrack

generic

17.1 · 17.2 · 17.3

nvd

oracle

managed file transfer

generic

12.2.1.3.0 · 12.2.1.4.0

nvd

oracle

mysql enterprise monitor

generic

≤ 8.0.23

nvd

oracle

siebel ui framework

generic

≤ 21.9

osv

org.apache.tomcat

tomcat-coyote

generic

≥ 10.0.0 and ＜ 10.0.2

osv

org.apache.tomcat.embed

tomcat-embed-core

generic

≥ 8.5.0 and ＜ 8.5.63 · ≥ 9.0.0 and ＜ 9.0.43 · ≥ 10.0.0 and ＜ 10.0.2

References

URL	Tags
https://www.oracle.com/security-alerts/cpuoct2021.html	WEB
https://www.oracle.com/security-alerts/cpujan2022.html	WEB
https://www.oracle.com//security-alerts/cpujul2021.html	WEB
https://www.debian.org/security/2021/dsa-4891	WEB
https://security.netapp.com/advisory/ntap-20210409-0002	WEB
https://security.gentoo.org/glsa/202208-34	WEB
https://lists.debian.org/debian-lts-announce/2021/03/msg00018.html	WEB
https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9@%3Cdev.tomcat.apache.org%3E	WEB
https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9%40%3Cdev.tomcat.apache.org%3E	WEB
https://lists.apache.org/thread.html/rd0463f9a5cbc02a485404c4b990f0da452e5ac5c237808edba11c947@%3Cusers.tomcat.apache.org%3E	WEB

URL

Timeline

Published	2021-03-01	By the CVE Program.
ARMR remediation created	2021-11-23	Earliest commit adding this CVE's ARMR patch or security rule.
ARMR remediation last updated	2026-03-04	Most recent commit touching this CVE's ARMR patch or security rule.
Last VRT activity	2026-03-04	Most recent commit touching this CVE's classification, patch or rule file.
NVD record modified	2026-10-08	NVD's own last-modified date for this record.

Published

2021-03-01

By the CVE Program.

ARMR remediation created

2021-11-23

Earliest commit adding this CVE's ARMR patch or security rule.

ARMR remediation last updated

2026-03-04

Most recent commit touching this CVE's ARMR patch or security rule.

Last VRT activity

2026-03-04

Most recent commit touching this CVE's classification, patch or rule file.

NVD record modified

2026-10-08

NVD's own last-modified date for this record.

How VRT decided (2 of 24 rules ran)

2 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file decided it matched Protected by Waratek ARMR patch file exists for this CVE

3 armr-secure-rule-file not reached An ARMR security-rule template on disk for this CVE

4 manual-classification not reached A researcher's recorded decision for this specific CVE

5 manual classification not reached Manual classification of this CVE in the legacy dataset

6 non-java-upstream not reached A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component not reached The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side not reached Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven not reached An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead

10 cna-maven-package not reached An affected Maven artifact named by the CNA itself

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint not reached A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

18 open-source-maven not reached The affected package being open source on Maven, so the fix can be read

19 poc-derivable not reached An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit not reached Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

21 secure-rule-match not reached A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc not reached Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold not reached Medium or Low severity, no CISA or VulnCheck KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

24 no-exploit-published not reached Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

NVD ↗ · CVE.org ↗