{"id":"CVE-2021-33037","title":"Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse pr…","summary":"Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse pr…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","cwe":["CWE-444","CWE-444"],"vendor":"apache","product":"tomcat","affected":["tomcat >= 8.5.0, <= 8.5.66","tomcat > 9.0.0, <= 9.0.46","tomcat > 10.0.0, <= 10.0.6","tomee = 8.0.6","debian_linux = 9.0","debian_linux = 10.0","agile_product_lifecycle_management = 9.3.6","communications_cloud_native_core_policy = 1.14.0","communications_cloud_native_core_service_communication_proxy = 1.14.0","communications_diameter_signaling_router >= 8.0.0.0, <= 8.5.0.2","communications_instant_messaging_server = 10.0.1.5.0","communications_policy_management = 12.5.0","communications_pricing_design_center = 12.0.0.3.0","communications_session_report_manager >= 8.0.0, <= 8.2.4.0","communications_session_route_manager >= 8.0.0, <= 8.2.4","graph_server_and_client < 21.4","healthcare_translational_research = 4.1.0","hospitality_cruise_shipboard_property_management_system = 20.1.0","instantis_enterprisetrack = 17.1","instantis_enterprisetrack = 17.2","instantis_enterprisetrack = 17.3","managed_file_transfer = 12.2.1.3.0","managed_file_transfer = 12.2.1.4.0","mysql_enterprise_monitor <= 8.0.25","sd-wan_edge = 9.0","sd-wan_edge = 9.1","secure_global_desktop = 5.6","utilities_testing_accelerator = 6.0.0.1.1","utilities_testing_accelerator = 6.0.0.2.2","utilities_testing_accelerator = 6.0.0.3.1","epolicy_orchestrator < 5.10.0","epolicy_orchestrator = 5.10.0"],"patched":["graph_server_and_client 21.4","epolicy_orchestrator 5.10.0"],"published":"2021-07-12","updated":"2026-08-25","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-33037","references":[{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10366","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r290aee55b72811fd19e75ac80f6143716c079170c5671b96932ed44b%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r40f921575aee8d7d34e53182f862c45cbb8f3d898c9d4e865c2ec262%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r612a79269b0d5e5780c62dfd34286a8037232fec0bc6f1a7e60c9381%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rc6ef52453bb996a98cb45442871a1db56b7c349939e45d829bf9ae37%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rd0dfea39829bc0606c936a16f6fca338127c86c0a1083970b45ac8d2%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/re01e7e93154e8bdf78a11a23f9686427bd3d51fc6e12c508645567b7%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rf1b54fd3f52f998ca4829159a88cc4c23d6cef5c6447d00948e75c97%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00009.html","label":"security@apache.org"},{"url":"https://security.gentoo.org/glsa/202208-34","label":"security@apache.org"},{"url":"https://security.netapp.com/advisory/ntap-20210827-0007/","label":"security@apache.org"},{"url":"https://www.debian.org/security/2021/dsa-4952","label":"security@apache.org"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","label":"security@apache.org"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10366","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r290aee55b72811fd19e75ac80f6143716c079170c5671b96932ed44b%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r40f921575aee8d7d34e53182f862c45cbb8f3d898c9d4e865c2ec262%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r612a79269b0d5e5780c62dfd34286a8037232fec0bc6f1a7e60c9381%40%3Cannounce.tomcat.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rc6ef52453bb996a98cb45442871a1db56b7c349939e45d829bf9ae37%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rd0dfea39829bc0606c936a16f6fca338127c86c0a1083970b45ac8d2%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/re01e7e93154e8bdf78a11a23f9686427bd3d51fc6e12c508645567b7%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rf1b54fd3f52f998ca4829159a88cc4c23d6cef5c6447d00948e75c97%40%3Ccommits.tomee.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00009.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202208-34","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210827-0007/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4952","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.75353,"epssPercentile":0.99492,"ingestedAt":"2026-08-25T17:29:31.279Z","slug":"CVE-2021-33037","body":"## Overview\n\nApache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse proxy. Specifically: - Tomcat incorrectly ignored the transfer encoding header if the client declared it would only accept an HTTP/1.0 response; - Tomcat honoured the identify encoding; and - Tomcat did not ensure that, if present, the chunked encoding was the final encoding.\n\n## Affected\n\n- `tomcat >= 8.5.0, <= 8.5.66`\n- `tomcat > 9.0.0, <= 9.0.46`\n- `tomcat > 10.0.0, <= 10.0.6`\n- `tomee = 8.0.6`\n- `debian_linux = 9.0`\n- `debian_linux = 10.0`\n- `agile_product_lifecycle_management = 9.3.6`\n- `communications_cloud_native_core_policy = 1.14.0`\n- `communications_cloud_native_core_service_communication_proxy = 1.14.0`\n- `communications_diameter_signaling_router >= 8.0.0.0, <= 8.5.0.2`\n- `communications_instant_messaging_server = 10.0.1.5.0`\n- `communications_policy_management = 12.5.0`\n- `communications_pricing_design_center = 12.0.0.3.0`\n- `communications_session_report_manager >= 8.0.0, <= 8.2.4.0`\n- `communications_session_route_manager >= 8.0.0, <= 8.2.4`\n- `graph_server_and_client < 21.4`\n- `healthcare_translational_research = 4.1.0`\n- `hospitality_cruise_shipboard_property_management_system = 20.1.0`\n- `instantis_enterprisetrack = 17.1`\n- `instantis_enterprisetrack = 17.2`\n- `instantis_enterprisetrack = 17.3`\n- `managed_file_transfer = 12.2.1.3.0`\n- `managed_file_transfer = 12.2.1.4.0`\n- `mysql_enterprise_monitor <= 8.0.25`\n- `sd-wan_edge = 9.0`\n- `sd-wan_edge = 9.1`\n- `secure_global_desktop = 5.6`\n- `utilities_testing_accelerator = 6.0.0.1.1`\n- `utilities_testing_accelerator = 6.0.0.2.2`\n- `utilities_testing_accelerator = 6.0.0.3.1`\n- `epolicy_orchestrator < 5.10.0`\n- `epolicy_orchestrator = 5.10.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `graph_server_and_client 21.4`\n- `epolicy_orchestrator 5.10.0`","depth":"sunlit","depthScore":44,"depthScoreParts":{"impact":29.2,"likelihood":15.1,"exploitation":0,"ransomware":0},"changes":[]}