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CVE-2020-11996

31
FAUCET Score

CVE-2020-11996 describes a denial-of-service vulnerability in Apache Tomcat versions 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35, and 8.5.0 to 8.5.55, affecting various distributions including Canonical, Debian, and Oracle. This flaw allows an unauthenticated attacker to trigger high CPU usage and potential server unresponsiveness through specially crafted HTTP/2 requests. Rated with a CVSS score of 7.5 (High), the vulnerability has a low attack complexity and can lead to a complete loss of availability. Despite its severity, 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, <= 8.5.55CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
>= 9.0.0, <= 9.0.35CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone1:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone10:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone11:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
26.70%
Probability of exploitation in next 30 days
EPSS Percentile
97.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.2670 is in the 96th percentile among its peer group of 51,506 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (24)

mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 10.0.0-M5
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 9.0.35
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcatFixed in: 8.5.55
mavenpatch availablevia ghsa
Product: org.apache.tomcat.embed:tomcat-embed-coreFixed in: 10.0.0-M5
mavenpatch availablevia ghsa
Product: org.apache.tomcat.embed:tomcat-embed-coreFixed in: 9.0.35
mavenpatch availablevia ghsa
Product: org.apache.tomcat.embed:tomcat-embed-coreFixed in: 8.5.55
redhatpatch availablevia redhat_api
Product: Red Hat Fuse 7.9Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 6Fixed in: jws5-jboss-logging-0:3.4.1-1.Final_redhat_00001.1.el6jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 6Fixed in: jws5-mod_cluster-0:1.4.2-7.Final_redhat_00002.2.el6jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 6Fixed in: jws5-tomcat-0:9.0.36-6.redhat_5.2.el6jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 6Fixed in: jws5-tomcat-native-0:1.2.25-2.redhat_2.el6jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-jboss-logging-0:3.4.1-1.Final_redhat_00001.1.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-mod_cluster-0:1.4.2-7.Final_redhat_00002.2.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-tomcat-0:9.0.36-6.redhat_5.2.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-tomcat-native-0:1.2.25-2.redhat_2.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-jboss-logging-0:3.4.1-1.Final_redhat_00001.1.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-mod_cluster-0:1.4.2-7.Final_redhat_00002.2.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-tomcat-0:9.0.36-6.redhat_5.2.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-tomcat-native-0:1.2.25-2.redhat_2.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat support for Spring Boot 2.3.6Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Text-Only RHOAR
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: pki-deps:10.6/pki-servlet-engine
redhatend of lifevia redhat_api
Product: Red Hat OpenStack Platform 13 (Queens)Fixed in: opendaylight

Vendor Advisories (2)

mavenGHSA-53hp-jpwq-2jgqhigh

Uncontrolled Resource Consumption in Apache Tomcat

Feb 9, 2022
redhatCVE-2020-11996Moderate

tomcat: specially crafted sequence of HTTP/2 requests can lead to DoS

Jun 25, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-07/msg00064.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-07/msg00072.html
Mailing ListThird Party Advisory
lists.apache.org / thread.html/r2529016c311ce9485e6f173446d469600fdfbb94dccadfcd9dfdac79%40%3Cusers.tomcat.apache.org%3E
lists.apache.org / thread.html/r3ea96d8f36dd404acce83df8aeb22a9e807d6c13ca9c5dec72f872cd%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E
Mailing ListVendor Advisory
lists.apache.org / thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/r6c29801370a36c1a5159679269777ad0c73276d3015b8bbefea66e5c%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/r74f5a8204efe574cbfcd95b2a16236fe95beb45c4d9fee3dc789dca9%40%3Ccommits.ofbiz.apache.org%3E
lists.apache.org / thread.html/r8f3d416c193bc9384a8a7dd368623d441f5fcaff1057115008100561%40%3Ccommits.ofbiz.apache.org%3E
lists.apache.org / thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/r93ca628ef3a4530dfe5ac49fddc795f0920a4b2a408b57a30926a42b%40%3Ccommits.ofbiz.apache.org%3E
lists.apache.org / thread.html/r9ad911fe49450ed9405827af0e7a74104041081ff91864b1f2546bbd%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/rb4ee49ecc4c59620ffd5e66e84a17e526c2c3cfa95d0cd682d90d338%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/rb820f1a2a02bf07414be12c653c2ab5321fd87b9bf6c5e635c53ff4b%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/rc80b96b4b96618b2b7461cb90664a428cfd6605eea9f74e51b792542%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/rea65d6ef2e45dd1c45faae83922042732866c7b88fa109b76c83db52%40%3Cnotifications.ofbiz.apache.org%3E
lists.apache.org / thread.html/ref0339792ac6dac1dba83c071a727ad72380899bde60f6aaad4031b9%40%3Cnotifications.ofbiz.apache.org%3E
lists.debian.org / debian-lts-announce/2020/07/msg00010.html
Mailing ListThird Party Advisory
security.netapp.com / advisory/ntap-20200709-0002
Third Party Advisory
usn.ubuntu.com / 4596-1
Third Party Advisory
debian.org / security/2020/dsa-4727
Third Party Advisory
oracle.com / security-alerts/cpujan2021.html
Third Party Advisory
oracle.com / security-alerts/cpuoct2020.html
Third Party Advisory