{"id":"CVE-2021-33037","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-33037","generatedAt":"2026-11-05T01:11:08.982Z","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 proxy.","description":"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 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.","published":"2021-07-12T15:15:08.000Z","lastModified":"2026-10-08T22:17:10.000Z","status":"Modified","sourceIdentifier":"security@apache.org","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"cwe":["CWE-444"],"affected":["apache/tomcat","apache/tomee","debian/debian linux","oracle/agile product lifecycle management","oracle/communications cloud native core policy","oracle/communications cloud native core service communication proxy","oracle/communications diameter signaling router","oracle/communications instant messaging server","oracle/communications policy management","oracle/communications pricing design center","oracle/communications session report manager","oracle/communications session route manager","oracle/graph server and client","oracle/healthcare translational research","oracle/hospitality cruise shipboard property management system","oracle/instantis enterprisetrack","oracle/managed file transfer","oracle/mysql enterprise monitor","oracle/sd-wan edge","oracle/secure global desktop","oracle/utilities testing accelerator","mcafee/epolicy orchestrator"],"epss":{"score":0.74667,"percentile":0.99502,"date":"2026-11-03","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 74.7%, higher than 100% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10366","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r290aee55b72811fd19e75ac80f6143716c079170c5671b96932ed44b%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r40f921575aee8d7d34e53182f862c45cbb8f3d898c9d4e865c2ec262%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r612a79269b0d5e5780c62dfd34286a8037232fec0bc6f1a7e60c9381%40%3Cannounce.tomcat.apache.org%3E","tags":["Mailing List","Vendor Advisory"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rc6ef52453bb996a98cb45442871a1db56b7c349939e45d829bf9ae37%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rd0dfea39829bc0606c936a16f6fca338127c86c0a1083970b45ac8d2%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/re01e7e93154e8bdf78a11a23f9686427bd3d51fc6e12c508645567b7%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rf1b54fd3f52f998ca4829159a88cc4c23d6cef5c6447d00948e75c97%40%3Ccommits.tomee.apache.org%3E","source":"security@apache.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://security.gentoo.org/glsa/202208-34","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://security.netapp.com/advisory/ntap-20210827-0007/","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.debian.org/security/2021/dsa-4952","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10366","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r290aee55b72811fd19e75ac80f6143716c079170c5671b96932ed44b%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r40f921575aee8d7d34e53182f862c45cbb8f3d898c9d4e865c2ec262%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r612a79269b0d5e5780c62dfd34286a8037232fec0bc6f1a7e60c9381%40%3Cannounce.tomcat.apache.org%3E","tags":["Mailing List","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rc6ef52453bb996a98cb45442871a1db56b7c349939e45d829bf9ae37%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rd0dfea39829bc0606c936a16f6fca338127c86c0a1083970b45ac8d2%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/re01e7e93154e8bdf78a11a23f9686427bd3d51fc6e12c508645567b7%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rf1b54fd3f52f998ca4829159a88cc4c23d6cef5c6447d00948e75c97%40%3Ccommits.tomee.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202208-34","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210827-0007/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4952","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33037","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}