CVE-2023-45648: Apache Tomcat

Medium severity, CVSS 5.3. EPSS: 5.8% chance of exploitation in the next 30 days.

Improper Input Validation vulnerability in Apache Tomcat.Tomcat from 11.0.0-M1 through 11.0.0-M11, from 10.1.0-M1 through 10.1.13, from 9.0.0-M1 through 9.0.81 and from 8.5.0 through 8.5.93 did not correctly parse HTTP trailer headers. A specially crafted, invalid trailer header could cause Tomcat to treat a single request as multiple requests leading to the possibility of request smuggling when behind a reverse proxy. Older, EOL versions may also be affected. Users are recommended to upgrade to version 11.0.0-M12 onwards, 10.1.14 onwards, 9.0.81 onwards or 8.5.94 onwards, which fix the issue.

Affected products

• Apache Tomcat: from 8.5.0, before 8.5.94 (fixed in 8.5.94); from 9.0.1, before 9.0.81 (fixed in 9.0.81); from 10.1.1, before 10.1.14 (fixed in 10.1.14); version 9.0.0 only; version 10.1.0 only; version 11.0.0 only
• Debian Debian Linux: version 10.0 only; version 11.0 only; version 12.0 only

Published 2023-10-10. Last modified 2026-06-17.