{"id":"CVE-2020-11996","title":"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","summary":"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 c…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"apache","product":"tomcat","affected":["tomcat >= 8.5.0, <= 8.5.55","tomcat >= 9.0.0, <= 9.0.35","tomcat = 9.0.0","tomcat = 10.0.0","ubuntu_linux = 20.04","mysql_enterprise_monitor <= 8.0.21","siebel_ui_framework <= 20.12","workload_manager = 12.2.0.1","workload_manager = 18c","workload_manager = 19c","leap = 15.1","leap = 15.2","debian_linux = 9.0","debian_linux = 10.0","oncommand_system_manager = 3.0","oncommand_system_manager = 3.1.3"],"published":"2020-06-26","updated":"2026-10-08","sourceUpdated":"2026-10-08T22:16:56.027","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-11996","references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.html","label":"security@apache.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.html","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r2529016c311ce9485e6f173446d469600fdfbb94dccadfcd9dfdac79%40%3Cusers.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r3ea96d8f36dd404acce83df8aeb22a9e807d6c13ca9c5dec72f872cd%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r6c29801370a36c1a5159679269777ad0c73276d3015b8bbefea66e5c%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r74f5a8204efe574cbfcd95b2a16236fe95beb45c4d9fee3dc789dca9%40%3Ccommits.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r8f3d416c193bc9384a8a7dd368623d441f5fcaff1057115008100561%40%3Ccommits.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r93ca628ef3a4530dfe5ac49fddc795f0920a4b2a408b57a30926a42b%40%3Ccommits.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r9ad911fe49450ed9405827af0e7a74104041081ff91864b1f2546bbd%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rb4ee49ecc4c59620ffd5e66e84a17e526c2c3cfa95d0cd682d90d338%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rb820f1a2a02bf07414be12c653c2ab5321fd87b9bf6c5e635c53ff4b%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rc80b96b4b96618b2b7461cb90664a428cfd6605eea9f74e51b792542%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rea65d6ef2e45dd1c45faae83922042732866c7b88fa109b76c83db52%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/ref0339792ac6dac1dba83c071a727ad72380899bde60f6aaad4031b9%40%3Cnotifications.ofbiz.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html","label":"security@apache.org"},{"url":"https://security.netapp.com/advisory/ntap-20200709-0002/","label":"security@apache.org"},{"url":"https://usn.ubuntu.com/4596-1/","label":"security@apache.org"},{"url":"https://www.debian.org/security/2020/dsa-4727","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2021.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuoct2020.html","label":"security@apache.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r2529016c311ce9485e6f173446d469600fdfbb94dccadfcd9dfdac79%40%3Cusers.tomcat.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r3ea96d8f36dd404acce83df8aeb22a9e807d6c13ca9c5dec72f872cd%40%3Cnotifications.ofbiz.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r5a4f80a6acc6607d61dae424b643b594c6188dd4e1eff04705c10db2%40%3Cnotifications.ofbiz.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r6c29801370a36c1a5159679269777ad0c73276d3015b8bbefea66e5c%40%3Cnotifications.ofbiz.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r74f5a8204efe574cbfcd9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Overview\n\nA 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.\n\n## Affected\n\n- `tomcat >= 8.5.0, <= 8.5.55`\n- `tomcat >= 9.0.0, <= 9.0.35`\n- `tomcat = 9.0.0`\n- `tomcat = 10.0.0`\n- `ubuntu_linux = 20.04`\n- `mysql_enterprise_monitor <= 8.0.21`\n- `siebel_ui_framework <= 20.12`\n- `workload_manager = 12.2.0.1`\n- `workload_manager = 18c`\n- `workload_manager = 19c`\n- `leap = 15.1`\n- `leap = 15.2`\n- `debian_linux = 9.0`\n- `debian_linux = 10.0`\n- `oncommand_system_manager = 3.0`\n- `oncommand_system_manager = 3.1.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":59,"depthScoreParts":{"impact":41.3,"likelihood":5.3,"exploitation":12,"ransomware":0},"changes":[]}