Apache Tomcat Improper Input Validation vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

• CVE-2023-45648: 5.88% estimated exploitation activity in the next 30 days; percentile 93.23 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

10 Oct 2023, 21:31 UTC

Last modified by the source

12 Jun 2026, 19:57 UTC

Source last checked

26 Oct 2026, 16:53 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-r6j3-px5g-cq3x

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# Patch Next advisory brief: CVE-2023-45648

Advisory: Apache Tomcat Improper Input Validation vulnerability
IDs: CVE-2023-45648, GHSA-r6j3-px5g-cq3x
Record: https://patchnext.com/advisories/cve-2023-45648 (revision 1, source checked 26 Oct 2026, 16:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.tomcat:tomcat-coyote 11.0.0-M12, 10.1.14, 9.0.81, 8.5.94; org.apache.tomcat.embed:tomcat-embed-core 11.0.0-M12, 10.1.14, 9.0.81, 8.5.94; org.apache.tomcat:tomcat 11.0.0-M12, 10.1.14, 9.0.81, 8.5.94. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat:tomcat-coyote: affected >= 11.0.0-M1, < 11.0.0-M12; >= 10.1.0-M1, < 10.1.14; >= 9.0.0-M1, < 9.0.81; >= 8.5.0, < 8.5.94; fixed in 10.1.14, 9.0.81, 11.0.0-M12, 8.5.94
- Maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 11.0.0-M1, < 11.0.0-M12; >= 10.1.0-M1, < 10.1.14; >= 9.0.0-M1, < 9.0.81; >= 8.5.0, < 8.5.94; fixed in 10.1.14, 9.0.81, 11.0.0-M12, 8.5.94
- Maven org.apache.tomcat:tomcat: affected >= 11.0.0-M1, < 11.0.0-M12; >= 10.1.0-M1, < 10.1.14; >= 9.0.0-M1, < 9.0.81; >= 8.5.0, < 8.5.94; fixed in 10.1.14, 9.0.81, 11.0.0-M12, 8.5.94

## Suggested inspection (read-only)
- Maven org.apache.tomcat:tomcat-coyote: check the installed version with your package manager.
- Maven org.apache.tomcat.embed:tomcat-embed-core: check the installed version with your package manager.
- Maven org.apache.tomcat:tomcat: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.tomcat:tomcat-coyote, org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-r6j3-px5g-cq3x (GitHub-reviewed advisory GHSA-r6j3-px5g-cq3x lists affected ranges: Maven org.apache.tomcat:tomcat >=11.0.0-M1 =10.1.0-M1 =9.0.0-M1 =8.5.0 =11.0.0-M1 =10.1.0-M1 =9.0.0-M1 =8.5.0 =11.0.0-M1 =10.1.0-M1 =9.0.0-M1 =8.5.0 <8.5.94)

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