CVE-2025-53506

Publication date 10 July 2025

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

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. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
tomcat10	25.04 plucky	Vulnerable
	24.04 LTS noble	Vulnerable
	22.04 LTS jammy	Not in release
tomcat11	25.04 plucky	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
tomcat9	25.04 plucky	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Vulnerable
	20.04 LTS focal	Vulnerable
	18.04 LTS bionic	Vulnerable

Notes

ebarretto

From Debian: Starting with 9.0.70-2 src:tomcat9 no longer ships the server stack, using that as the fixed version

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H