CVE Feed

    Dashboard / CVE / CVE-2020-11996

    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 8.5.0 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.

    Published:Jun 25, 2020
    Last Modified:Nov 21, 2024
    EPS:Jun 26, 2020
    EPSS Score:0.31135
    CVSS Score:7.5

    Affected Products

    Vendor
    Apache
    Product
    Tomcat
    Vendor
    Canonical
    Product
    Ubuntu Linux
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Netapp
    Product
    Oncommand System Manager
    Vendor
    Opensuse
    Product
    Leap
    Vendor
    Oracle
    Product
    Mysql Enterprise Monitor
    Vendor
    Oracle
    Product
    Siebel Ui Framework
    Vendor
    Oracle
    Product
    Workload Manager
    Vendor
    Redhat
    Product
    Jboss Enterprise Web Server
    Vendor
    Redhat
    Product
    Jboss Fuse
    Vendor
    Redhat
    Product
    Openshift Application Runtimes

    Exploits

    https://github.com/rusakovichma/tomcat-embed-core-9.0.31-CVE-2020-11996

    Related CVEs

    CVE-2026-73180 (CVSS 6.8) — Insufficient Session Expiration vulnerability in Apache Tomcat meant that if the session ID for an authenticat…
    CVE-2026-68763 (CVSS 7.5) — Uncontrolled Resource Consumption vulnerability in Apache Tomcat via an allocation leak in the HTTP/2 backlog …
    CVE-2026-68569 (CVSS 8.1) — Improper Authentication vulnerability in Apache Tomcat meant that in some circumstances (e.g. CLIENT-CERT, SPN…
    CVE-2026-68525 (CVSS 9.1) — Incorrect Authorization vulnerability in Apache Tomcat's FORM authentication process allows the bypassing of a…
    CVE-2026-66422 (CVSS 8.1) — Improper Authorization vulnerability in Apache Tomcat cause by security-role-ref definitions being incorrectly…
    CVE-2026-65927 (CVSS 7.5) — Off-by-one Error vulnerability in Apache Tomcat impacting the [N] flag on the rewrite valves causes rewrite pr…
    CVE-2026-65905 (CVSS 9.8) — Authentication Bypass by Capture-replay vulnerability in Apache Tomcat's DIGEST authenticator. If, before wind…
    CVE-2026-65637 (CVSS 9.8) — Improper Input Validation vulnerability in Apache Tomcat due to incomplete fix for CVE-2026-32990. This iss…
    CVE-2026-65183 (CVSS 8.1) — Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in Apache Tomcat when creating unix domain soc…
    CVE-2026-65182 (CVSS 9.1) — Improper Access Control, Incorrect Authorization vulnerability in Apache Tomcat leads to security constraint b…

    References

    http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.html
    http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.html
    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%3E
    https://lists.apache.org/thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r6c29801370a36c1a5159679269777ad0c73276d3015b8bbefea66e5c%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r74f5a8204efe574cbfcd95b2a16236fe95beb45c4d9fee3dc789dca9%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r8f3d416c193bc9384a8a7dd368623d441f5fcaff1057115008100561%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r93ca628ef3a4530dfe5ac49fddc795f0920a4b2a408b57a30926a42b%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r9ad911fe49450ed9405827af0e7a74104041081ff91864b1f2546bbd%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rb4ee49ecc4c59620ffd5e66e84a17e526c2c3cfa95d0cd682d90d338%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rb820f1a2a02bf07414be12c653c2ab5321fd87b9bf6c5e635c53ff4b%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rc80b96b4b96618b2b7461cb90664a428cfd6605eea9f74e51b792542%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rea65d6ef2e45dd1c45faae83922042732866c7b88fa109b76c83db52%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/ref0339792ac6dac1dba83c071a727ad72380899bde60f6aaad4031b9%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html
    https://security.netapp.com/advisory/ntap-20200709-0002/
    https://usn.ubuntu.com/4596-1/
    https://www.debian.org/security/2020/dsa-4727
    https://www.oracle.com/security-alerts/cpujan2021.html
    https://www.oracle.com/security-alerts/cpuoct2020.html
    http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.html
    http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.html
    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%3E
    https://lists.apache.org/thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r6c29801370a36c1a5159679269777ad0c73276d3015b8bbefea66e5c%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r74f5a8204efe574cbfcd95b2a16236fe95beb45c4d9fee3dc789dca9%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r8f3d416c193bc9384a8a7dd368623d441f5fcaff1057115008100561%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r93ca628ef3a4530dfe5ac49fddc795f0920a4b2a408b57a30926a42b%40%3Ccommits.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/r9ad911fe49450ed9405827af0e7a74104041081ff91864b1f2546bbd%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rb4ee49ecc4c59620ffd5e66e84a17e526c2c3cfa95d0cd682d90d338%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rb820f1a2a02bf07414be12c653c2ab5321fd87b9bf6c5e635c53ff4b%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rc80b96b4b96618b2b7461cb90664a428cfd6605eea9f74e51b792542%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/rea65d6ef2e45dd1c45faae83922042732866c7b88fa109b76c83db52%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.apache.org/thread.html/ref0339792ac6dac1dba83c071a727ad72380899bde60f6aaad4031b9%40%3Cnotifications.ofbiz.apache.org%3E
    https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html
    https://security.netapp.com/advisory/ntap-20200709-0002/
    https://usn.ubuntu.com/4596-1/
    https://www.debian.org/security/2020/dsa-4727
    https://www.oracle.com/security-alerts/cpujan2021.html
    https://www.oracle.com/security-alerts/cpuoct2020.html

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High