Disclosure summary
Improper Input Validation vulnerability in Apache Tomcat. Tomcat from 11.0.0-M1 through 11.0.0-M10, from 10.1.0-M1 through 10.1.15, from 9.0.0-M1 through 9.0.82, and from 8.5.0 through 8.5.95 did not correctly parse HTTP trailer headers. A trailer header that exceeded the header size limit 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-M11 onwards, 10.1.16 onwards, 9.0.83 onwards or 8.5.96 onwards, which fix the issue.
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
GitHub Reviewed Security Advisories · GHSA-fccv-jmmp-qg76
Open original source · Updated Oct 02, 2026
Apache Tomcat Improper Input Validation vulnerability
Source severity: HIGH / 0
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| maven | org.apache.tomcat:tomcat-catalina | >= 11.0.0-M1, < 11.0.0-M11 | 11.0.0-M11 |
| maven | org.apache.tomcat:tomcat-catalina | >= 10.1.0-M1, < 10.1.16 | 10.1.16 |
| maven | org.apache.tomcat:tomcat-catalina | >= 9.0.0-M1, < 9.0.83 | 9.0.83 |
| maven | org.apache.tomcat:tomcat-catalina | >= 8.5.0, < 8.5.96 | 8.5.96 |
| maven | org.apache.tomcat.embed:tomcat-embed-core | >= 11.0.0-M1, < 11.0.0-M11 | 11.0.0-M11 |
| maven | org.apache.tomcat.embed:tomcat-embed-core | >= 10.1.0-M1, < 10.1.16 | 10.1.16 |
| maven | org.apache.tomcat.embed:tomcat-embed-core | >= 9.0.0-M1, < 9.0.83 | 9.0.83 |
| maven | org.apache.tomcat.embed:tomcat-embed-core | >= 8.5.0, < 8.5.96 | 8.5.96 |
| maven | org.apache.tomcat:tomcat-coyote | >= 11.0.0-M1, < 11.0.0-M11 | 11.0.0-M11 |
Original records & references
- NIST NVD record
- CVE Program record
- github.com — Reviewed advisory
PUBLISHED 2023-11-28T13:30:23-05:00
MODIFIED 2026-10-02T16:14:55-04:00
INGESTED 2026-10-06T11:45:17-04:00