Home/CVE/A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5
CVE

CVE-2020-11996

A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5

A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 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 could trigger high CPU usage for several seconds. If a sufficient number of such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.

HIGH · CVSS 7.5 EPSS 0.45121
Schedule remediation
  • EPSS ≥ 0.10 - elevated exploitation probability
  • EPSS percentile: top 2% of all CVEs by exploitation likelihood
  • CVSS base score ≥ 7.0
Sigma rules1 YARA rules0
▤

Affected Products & Versions

10
apache tomcat>= 8.5.0 and <= 8.5.55
apache tomcat>= 9.0.0 and <= 9.0.35
apache tomcatall versions
canonical ubuntu linuxall versions
oracle mysql enterprise monitor<= 8.0.21
oracle siebel ui framework<= 20.12
oracle workload managerall versions
opensuse leapall versions
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Maven org.apache.tomcat:tomcat HIGH fixed in 10.0.0-M5
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumTomcat WebServer Logs Deleted
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security@apache.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD26 Jun 2020 · 05:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
⚑

Vendor Advisories

14
suse-csafopenSUSE-SU-2024:11468-1
suse-csafopenSUSE-SU-2024:13441-1
rhsaRHSA-2021:3140Moderate
rhsaRHSA-2021:0292Important
rhsaRHSA-2020:5388Important
🔗

References & Sources

24
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.htmlMailing ListThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.htmlMailing ListThird Party Advisory
https://lists.apache.org/thread.html/r2529016c311ce9485e6f173446d469600fdfbb94dccadfcd9dfdac79%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/r3ea96d8f36dd404acce83df8aeb22a9e807d6c13ca9c5dec72f872cd%40%3Cnotifications.ofbiz.apache.org%3E
https://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3EMailing ListVendor Advisory
https://lists.apache.org/thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E
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