What’s Vulnerable › Vulnerabilities
CVE-2021-33037: Incorrect Transfer-Encoding handling with HTTP/1.0
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 74.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-07-12 · updated 2026-10-08
- Weakness: CWE-444
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.
Affected products
- Apache Tomcat: from 8.5.0 through 8.5.66; from 9.0.0 (excl.) through 9.0.46; from 10.0.0 (excl.) through 10.0.6
- Apache TomEE: 8.0.6
- Debian Linux: 9.0, 10.0
- McAfee,LLC McAfee ePolicy Orchestrator (ePO): before 5.10.0; 5.10.0, 5.10.0-update_1, 5.10.0-update_10, 5.10.0-update_2, 5.10.0-update_3, 5.10.0-update_4 (+5) — fixed in 5.10.0
- Oracle Corporation Oracle Agile PLM: 9.3.6
- Oracle Communications Cloud Native Core Policy: 1.14.0
- Oracle Communications Cloud Native Core Service Communication Proxy: 1.14.0
- Oracle Corporation Communications Diameter Signaling Router (DSR): from 8.0.0.0 through 8.5.0.2
- Oracle Communications Instant Messaging Server: 10.0.1.5.0
- Oracle Corporation Communications Policy Management: 12.5.0
- Oracle Corporation Communications Pricing Design Center: 12.0.0.3.0
- Oracle Communications Session Report Manager: from 8.0.0 through 8.2.4.0
- Oracle Communications Session Route Manager: from 8.0.0 through 8.2.4
- Oracle Graph Server And Client: before 21.4 — fixed in 21.4
- Oracle Healthcare Translational Research: 4.1.0
- Oracle Corporation Hospitality Cruise Shipboard Property Management System: 20.1.0
- Oracle Instantis Enterprisetrack: 17.1, 17.2, 17.3
- Oracle Corporation Oracle Managed File Transfer: 12.2.1.3.0, 12.2.1.4.0
- Oracle Corporation MySQL Enterprise Monitor: through 8.0.25
- Oracle Corporation SD-WAN Edge: 9.0, 9.1
- Oracle Corporation Secure Global Desktop: 5.6
- Oracle Utilities Testing Accelerator: 6.0.0.1.1, 6.0.0.2.2, 6.0.0.3.1
How to fix
Upgrade to a fixed version: McAfee,LLC McAfee ePolicy Orchestrator (ePO) 5.10.0; Oracle Graph Server And Client 21.4. Check the vendor advisory for mitigations.
References
- https://kc.mcafee.com/corporate/index?page=content&id=SB10366
- https://lists.apache.org/thread.html/r290aee55b72811fd19e75ac80f6143716c079170c5671b96932ed44b%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/r40f921575aee8d7d34e53182f862c45cbb8f3d898c9d4e865c2ec262%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/r612a79269b0d5e5780c62dfd34286a8037232fec0bc6f1a7e60c9381%40%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/rc6ef52453bb996a98cb45442871a1db56b7c349939e45d829bf9ae37%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rd0dfea39829bc0606c936a16f6fca338127c86c0a1083970b45ac8d2%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/re01e7e93154e8bdf78a11a23f9686427bd3d51fc6e12c508645567b7%40%3Ccommits.tomee.apache.org%3E
- https://lists.apache.org/thread.html/rf1b54fd3f52f998ca4829159a88cc4c23d6cef5c6447d00948e75c97%40%3Ccommits.tomee.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/08/msg00009.html
- https://security.gentoo.org/glsa/202208-34
- https://security.netapp.com/advisory/ntap-20210827-0007/
- https://www.debian.org/security/2021/dsa-4952
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