Expected Behavior Violation in Apache Tomcat

Exploitation

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

CVSS

9.8 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2017-5651: 7.75% estimated exploitation activity in the next 30 days; percentile 94.64 (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.

In Apache Tomcat 9.0.0.M1 to 9.0.0.M18 and 8.5.0 to 8.5.12, the refactoring of the HTTP connectors introduced a regression in the send file processing. If the send file processing completed quickly, it was possible for the Processor to be added to the processor cache twice. This could result in the same Processor being used for multiple requests which in turn could lead to unexpected errors and/or response mix-up.

Published by the source

13 May 2022, 01:46 UTC

Last modified by the source

18 Apr 2024, 17:11 UTC

Source last checked

26 Oct 2026, 16:29 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9hg2-395j-83rm

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# Patch Next advisory brief: CVE-2017-5651

Advisory: Expected Behavior Violation in Apache Tomcat
IDs: CVE-2017-5651, GHSA-9hg2-395j-83rm
Record: https://patchnext.com/advisories/cve-2017-5651 (revision 1, source checked 26 Oct 2026, 16:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.8)
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 9.0.0.M19, 8.5.13; org.apache.tomcat.embed:tomcat-embed-core 9.0.0.M19, 8.5.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat:tomcat-coyote: affected >= 9.0.0.M1, <= 9.0.0.M18; >= 8.5.0, <= 8.5.12; fixed in 9.0.0.M19, 8.5.13
- Maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 9.0.0.M1, <= 9.0.0.M18; >= 8.5.0, <= 8.5.12; fixed in 9.0.0.M19, 8.5.13

## 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.

## 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.
- 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-9hg2-395j-83rm (GitHub-reviewed advisory GHSA-9hg2-395j-83rm lists affected ranges: Maven org.apache.tomcat:tomcat-coyote >=9.0.0.M1 =8.5.0 =9.0.0.M1 =8.5.0 <=8.5.12)

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