CVE-2025-53506
Apache Tomcat: DoS via excessive h2 streams at connection start
- State
- Published
- Severity
- 7.5 High
- Published
- Jul 10, 2025
- Updated
- Nov 4, 2025
- Reserved
- Jul 1, 2025
Description
Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial settings frame that reduces the maximum permitted concurrent streams.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected.
Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
- CWE-400 Uncontrolled Resource Consumption
Affected Products
| Product | Versions |
|---|---|
Apache TomcatApache Software Foundation |
|
References
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