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7.5
HIGH CVSS 3.1
CVE-2025-53506
Apache Tomcat: DoS via excessive h2 streams at connection start
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. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.

INFO

Published Date :

July 10, 2025, 8:15 p.m.

Last Modified :

Aug. 8, 2025, 1:15 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2025-53506 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Apache tomcat
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
Upgrade Apache Tomcat to a fixed version to prevent resource exhaustion.
  • Upgrade Tomcat to version 11.0.9 or later.
  • Upgrade Tomcat to version 10.1.43 or later.
  • Upgrade Tomcat to version 9.0.107 or later.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-53506.

URL Resource
https://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0 Issue Tracking Mailing List Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-53506 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-53506 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-53506 vulnerability anywhere in the article.

  • The Hacker News
⚡ Weekly Recap: WhatsApp 0-Day, Docker Bug, Salesforce Breach, Fake CAPTCHAs, Spyware App & More

Cybersecurity today is less about single attacks and more about chains of small weaknesses that connect into big risks. One overlooked update, one misused account, or one hidden tool in the wrong hand ... Read more

Published Date: Sep 01, 2025 (3 weeks, 1 day ago)
  • CybersecurityNews
Apache Tomcat Coyote Vulnerability Let Attackers Trigger DoS Attack

A newly disclosed flaw in Apache Tomcat’s Coyote engine—tracked as CVE-2025-53506—has surfaced in the latest round of HTTP/2 security advisories. First noted in the National Vulnerability Database fiv ... Read more

Published Date: Jul 15, 2025 (2 months, 1 week ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-53506 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Aug. 08, 2025

    Action Type Old Value New Value
    Changed 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. Older, 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. 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.
  • CVE Modified by [email protected]

    Aug. 07, 2025

    Action Type Old Value New Value
    Changed 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. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue. 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. Older, 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.
  • Initial Analysis by [email protected]

    Jul. 29, 2025

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:* versions from (including) 10.1.0 up to (including) 10.1.42 *cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:* versions from (including) 11.0.0 up to (including) 11.0.8 *cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:* versions from (including) 9.0.0 up to (including) 9.0.106
    Added Reference Type Apache Software Foundation: https://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0 Types: Issue Tracking, Mailing List, Vendor Advisory
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 11, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • New CVE Received by [email protected]

    Jul. 10, 2025

    Action Type Old Value New Value
    Added 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. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.
    Added CWE CWE-400
    Added Reference https://lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 7.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact