CVE-2026-87022: Apache Tomcat: WebSocket message smuggling with per-message-deflate
Apache Software Foundation · Apache Tomcat
Vendor fix available · Affected: Apache Software Foundation Apache Tomcat · Exploitation: not established
ExploitationNot established
Not in CISA KEV as of catalogue 2026.11.13 (13 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public: not seen
- Not establishedNothing in the sources we check
Higher than 45% of scored CVEs
DescriptionNVD
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.
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Published
- September 2026
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 23 Sep.
- Apache Tomcat 11.0.26 Fixes 15 Flaws Enabling Request Smuggling and DoSSecurityOnline · first in our coverage · mentions it in passing
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