CVE-2021-25122: Apache Tomcat

High severity, CVSS 7.5. EPSS: 18.1% chance of exploitation in the next 30 days.

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

Affected products

• Apache Tomcat: from 8.5.0, up to and including 8.5.61; from 9.0.0, up to and including 9.0.41; version 9.0.0 only; version 10.0.0 only
• Debian Debian Linux: version 9.0 only; version 10.0 only
• Oracle Agile Product Lifecycle Management: version 9.3.3 only; version 9.3.6 only
• Oracle Communications Cloud Native Core Policy: version 1.14.0 only
• Oracle Communications Cloud Native Core Security Edge Protection Proxy: version 1.6.0 only
• Oracle Communications Instant Messaging Server: version 10.0.1.5.0 only
• Oracle Database: version 12.2.0.1 only; version 19c only; version 21c only
• Oracle Graph Server And Client: before 21.3.0 (fixed in 21.3.0); version 21.3.0 only
• Oracle Instantis Enterprisetrack: version 17.1 only; version 17.2 only; version 17.3 only
• Oracle Managed File Transfer: version 12.2.1.3.0 only; version 12.2.1.4.0 only
• Oracle MySQL Enterprise Monitor: up to and including 8.0.23
• Oracle Siebel UI Framework: up to and including 21.9

Published 2021-03-01. Last modified 2026-10-08.