Apache Tomcat up to 11.0.25 WebSocket Message input validation

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k0.91

Summaryinfo

A vulnerability was found in Apache Tomcat up to 7.0.109/8.5.100/9.0.121/10.1.59/11.0.25. It has been classified as critical. The affected element is an unknown function of the component WebSocket Message Handler. This manipulation causes input validation. This vulnerability is handled as CVE-2026-87022. The attack can be initiated remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Apache Tomcat up to 7.0.109/8.5.100/9.0.121/10.1.59/11.0.25. It has been declared as critical. Affected by this vulnerability is an unknown code block of the component WebSocket Message Handler. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at lists.apache.org. This vulnerability is known as CVE-2026-87022 since 09/08/2026. The exploitation appears to be easy. The attack can be launched remotely. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/23/2026).

Upgrading to version 11.0.26, 10.1.60 or 9.1.22 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Tomcat 11.0.26/10.1.60/9.1.22

Timelineinfo

09/08/2026 CVE reserved
09/23/2026 +15 days Advisory disclosed
09/23/2026 +0 days VulDB entry created
09/23/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: apache.org

Advisory: lists.apache.org
Status: Confirmed

CVE: CVE-2026-87022 (🔒)
GCVE (CVE): GCVE-0-2026-87022
GCVE (VulDB): GCVE-100-408931

Entryinfo

Created: 09/23/2026 13:51
Changes: 09/23/2026 13:51 (55)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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