CVE-2026-77791 is a vulnerability in Apache Tomcat
Published on September 23, 2026
Apache Tomcat: DoS via busy wait during WebSocket close
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.
Vulnerability Analysis
CVE-2026-77791 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-77791 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-77791
Want to know whenever a new CVE is published for Apache Tomcat? stack.watch will email you.
Affected Versions
Apache Software Foundation Apache Tomcat:- Version 11.0.0-M5, <= 11.0.25 is affected.
- Version 10.1.8, <= 10.1.59 is affected.
- Version 9.0.74, <= 9.0.121 is affected.
- Version 8.5.88, <= 8.5.100 is affected.
- Before and including 7.0.109 is unaffected.