Description
Improper handling of length parameter inconsistency vulnerability in Apache Tomcat allows WebSocket message smuggling when per-message-deflate is used.



This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121.



The following versions were EOS at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.56 through 7.0.109. Other unsupported versions may also be affected.



Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.1.22, which fix the issue.
Published: 2026-09-23
Score: 7.5 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Wed, 23 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 23 Sep 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache tomcat
Vendors & Products Apache
Apache tomcat

Wed, 23 Sep 2026 11:45:00 +0000

Type Values Removed Values Added
Description Improper handling of length parameter inconsistency vulnerability in Apache Tomcat allows WebSocket message smuggling when per-message-deflate is used. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121. The following versions were EOS at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.56 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.1.22, which fix the issue.
Title Apache Tomcat: WebSocket message smuggling with per-message-deflate
Weaknesses CWE-130
References

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-09-23T14:27:37.246Z

Reserved: 2026-09-08T17:16:33.368Z

Link: CVE-2026-87022

cve-icon Vulnrichment

Updated: 2026-09-23T14:27:08.349Z

cve-icon NVD

Status : Received

Published: 2026-09-23T12:17:08.640

Modified: 2026-09-23T15:17:22.927

Link: CVE-2026-87022

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-23T16:45:03Z

Weaknesses