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CVE-2026-77791: CWE-400 Uncontrolled Resource Consumption in Apache Software Foundation Apache Tomcat

0
High
VulnerabilityCVE-2026-77791cvecve-2026-77791cwe-400
Published: 09/23/2026 (09/23/2026, 11:20:50 UTC)
Source: CVE Database V5
Vendor/Project: Apache Software Foundation
Product: Apache Tomcat

Description

Uncontrolled Resource Consumption vulnerability in Apache Tomcat during sending of WebSocket close message enabled a DoS attack. This issue affects Apache Tomcat: from 11.0.0-M5 through 11.0.25, from 10.1.8 through 10.1.59, from 9.0.74 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.88 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

CVSS v3.1

Score 7.5high

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected software

Apache Software Foundation

Apache Tomcat

Affected versions
>=11.0.0-M5 <=11.0.25>=10.1.8 <=10.1.59>=9.0.74 <=9.0.121>=8.5.88 <=8.5.100
Mavenmore threats →ai
org.apache.tomcat/tomcat
pkg:maven/org.apache.tomcat/tomcat
Affected versions
>=11.0.0-M5 <=11.0.25>=10.1.8 <=10.1.59>=9.0.74 <=9.0.121>=8.5.88 <=8.5.100

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/23/2026, 11:48:57 UTC

Technical Analysis

An uncontrolled resource consumption vulnerability (CWE-400) exists in Apache Tomcat's WebSocket close message handling, allowing an attacker to cause a denial-of-service condition. The vulnerability affects Apache Tomcat versions from 11.0.0-M5 through 11.0.25, 10.1.8 through 10.1.59, 9.0.74 through 9.0.121, and some older unsupported versions such as 8.5.88 through 8.5.100. The issue is resolved in Apache Tomcat versions 11.0.26, 10.1.60, and 9.0.122.

Potential Impact

Successful exploitation of this vulnerability can lead to denial-of-service by exhausting server resources during the processing of WebSocket close messages. This may disrupt availability of the affected Apache Tomcat server instances.

Mitigation Recommendations

Users should upgrade affected Apache Tomcat instances to versions 11.0.26, 10.1.60, or 9.0.122, which contain the official fix for this vulnerability. No other mitigation steps are indicated by the vendor advisory.

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Technical Details

Data Version
5.2
Assigner Short Name
apache
Date Reserved
2026-08-21T12:38:02.420Z
State
PUBLISHED

Threat ID: 6ab3b90df7a7c54106b30f13

Added to database: 09/23/2026, 11:33:33 UTC

Last enriched: 09/23/2026, 11:48:57 UTC

Last updated: 09/24/2026, 01:57:04 UTC

Views: 12

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