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Vulnerability record · CVE-2026-87022 · published 23 September 2026

CVE-2026-87022: Improper handling of length parameter inconsistency vulnerability in Apache Tomcat allows WebSocket message sm…

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.

7.5 CVSS 3.1 High EPSS 0.42% · top 66.0% CWE-130 · CWE-130 Awaiting Analysis
7.5CVSS 3.1 base score
0.42%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
23 Sep 2026Last modified by NVD

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.

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

References

LinkTags
https://lists.apache.org/thread/ypvlkjqsq0480fnk9jm6h9qllddwlw4w
http://www.openwall.com/lists/oss-security/2026/09/23/30

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Source: NIST National Vulnerability Database (record CVE-2026-87022), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.