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High, CVSS 7.5

Infinite Loop in Apache Tomcat

CVE-2020-13935GHSA-m7jv-hq7h-mq7c

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (org.apache.tomcat.embed:tomcat-embed-websocket 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105; org.apache.tomcat:tomcat-websocket 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105; org.apache.tomcat:tomcat 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • Maven org.apache.tomcat.embed:tomcat-embed-websocket

    Affected
    >= 7.0.27, < 7.0.105>= 8.5.0, < 8.5.57>= 9.0.0.M1, < 9.0.37>= 10.0.0-M1, < 10.0.0-M7
    Fixed in
    7.0.105, 10.0.0-M7, 9.0.37, 8.5.57

  • Maven org.apache.tomcat:tomcat-websocket

    Affected
    >= 10.0.0-M1, < 10.0.0-M7>= 9.0.0.M1, < 9.0.37>= 8.5.0, < 8.5.57>= 7.0.27, < 7.0.105
    Fixed in
    7.0.105, 10.0.0-M7, 9.0.37, 8.5.57

  • Maven org.apache.tomcat:tomcat

    Affected
    >= 10.0.0-M1, < 10.0.0-M7>= 9.0.0.M1, < 9.0.37>= 8.5.0, < 8.5.57>= 7.0.27, < 7.0.105
    Fixed in
    7.0.105, 10.0.0-M7, 9.0.37, 8.5.57

Sources

  • GitHub Advisory Database and maintainer security advisories on GitHub

    GitHub-reviewed advisory GHSA-m7jv-hq7h-mq7c lists affected ranges: Maven org.apache.tomcat:tomcat >=10.0.0-M1 =9.0.0.M1 =8.5.0 =7.0.27 =7.0.27 =8.5.0 =9.0.0.M1 =10.0.0-M1 =10.0.0-M1 =9.0.0.M1 =8.5.0 =7.0.27 <7.0.105

    VerifiedObserved Structured GitHub Advisory Database record (type=reviewed) from the GitHub REST API.

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2020-13935: 86.61% estimated exploitation activity in the next 30 days; percentile 99.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

The payload length in a WebSocket frame was not correctly validated in Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56 and 7.0.27 to 7.0.104. Invalid payload lengths could trigger an infinite loop. Multiple requests with invalid payload lengths could lead to a denial of service.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-m7jv-hq7h-mq7c

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-13935

Advisory: Infinite Loop in Apache Tomcat
IDs: CVE-2020-13935, GHSA-m7jv-hq7h-mq7c
Record: https://patchnext.com/advisories/cve-2020-13935 (revision 1, source checked 26 Oct 2026, 16:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
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.embed:tomcat-embed-websocket 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105; org.apache.tomcat:tomcat-websocket 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105; org.apache.tomcat:tomcat 10.0.0-M7, 9.0.37, 8.5.57, 7.0.105. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat.embed:tomcat-embed-websocket: affected >= 7.0.27, < 7.0.105; >= 8.5.0, < 8.5.57; >= 9.0.0.M1, < 9.0.37; >= 10.0.0-M1, < 10.0.0-M7; fixed in 7.0.105, 10.0.0-M7, 9.0.37, 8.5.57
- Maven org.apache.tomcat:tomcat-websocket: affected >= 10.0.0-M1, < 10.0.0-M7; >= 9.0.0.M1, < 9.0.37; >= 8.5.0, < 8.5.57; >= 7.0.27, < 7.0.105; fixed in 7.0.105, 10.0.0-M7, 9.0.37, 8.5.57
- Maven org.apache.tomcat:tomcat: affected >= 10.0.0-M1, < 10.0.0-M7; >= 9.0.0.M1, < 9.0.37; >= 8.5.0, < 8.5.57; >= 7.0.27, < 7.0.105; fixed in 7.0.105, 10.0.0-M7, 9.0.37, 8.5.57

## Suggested inspection (read-only)
- Maven org.apache.tomcat.embed:tomcat-embed-websocket: check the installed version with your package manager.
- Maven org.apache.tomcat:tomcat-websocket: 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.embed:tomcat-embed-websocket, org.apache.tomcat:tomcat-websocket, 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-m7jv-hq7h-mq7c (GitHub-reviewed advisory GHSA-m7jv-hq7h-mq7c lists affected ranges: Maven org.apache.tomcat:tomcat >=10.0.0-M1 =9.0.0.M1 =8.5.0 =7.0.27 =7.0.27 =8.5.0 =9.0.0.M1 =10.0.0-M1 =10.0.0-M1 =9.0.0.M1 =8.5.0 =7.0.27 <7.0.105)

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