GHSA-25xr-qj8w-c4vf BIT-tomcat-2025-53506 CVE-2025-53506
Apache Tomcat Coyote vulnerable to Denial of Service via excessive HTTP/2 streams
High
Maven
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 2.13%
- Chance of exploitation in the next 30 days. Higher than 81.95% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
- Available
- 2 packages have a fixed version
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.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.apache.tomcat.embed:tomcat-embed-core | >= 8.5.0, <= 8.5.100 |
No fix yet |
| org.apache.tomcat.embed:tomcat-embed-core | >= 9.0.0.M1, < 9.0.107 |
9.0.107 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 10.1.0-M1, < 10.1.43 |
10.1.43 |
| org.apache.tomcat.embed:tomcat-embed-core | >= 11.0.0-M1, < 11.0.9 |
11.0.9 |
| org.apache.tomcat:tomcat-coyote | >= 11.0.0-M1, < 11.0.9 |
11.0.9 |
| org.apache.tomcat:tomcat-coyote | >= 10.1.0-M1, < 10.1.43 |
10.1.43 |
| org.apache.tomcat:tomcat-coyote | >= 9.0.0.M1, < 9.0.107 |
9.0.107 |
| org.apache.tomcat:tomcat-coyote | >= 8.5.0, <= 8.5.100 |
No fix yet |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.apache.tomcat.embed:tomcat-embed-core Maven → 9.0.107
- maven
<dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-core</artifactId><version>9.0.107</version></dependency>- gradle
implementation("org.apache.tomcat.embed:tomcat-embed-core:9.0.107")
org.apache.tomcat:tomcat-coyote Maven → 11.0.9
- maven
<dependency><groupId>org.apache.tomcat</groupId><artifactId>tomcat-coyote</artifactId><version>11.0.9</version></dependency>- gradle
implementation("org.apache.tomcat:tomcat-coyote:11.0.9")
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Packages
Other links
- github.com/apache/tomcat/commit/2aa6261276ebe50b99276953591e3a2be7898bdb
- github.com/apache/tomcat/commit/434772930f362145516dd60681134e7f0cf8115b
- github.com/apache/tomcat/commit/be8f330f83ceddaf3baeed57522e571572b6b99b
- lists.apache.org/thread/p09775q0rd185m6zz98krg0fp45j8kr0
- lists.debian.org/debian-lts-announce/2025/07/msg00009.html
- openwall.com/lists/oss-security/2025/07/10/13
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-83qj-6fr2-vhqg Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-qppj-fm5r-hxr3 HTTP/2 Stream Cancellation Attack | Medium Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-xjgh-84hx-56c5 Unrestricted Upload of File with Dangerous Type Apache Tomcat | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| CVE-2020-1938 Improper Privilege Management in Tomcat | Critical Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-pjfr-qf3p-3q25 When running Apache Tomcat on Windows with HTTP PUTs enabled it was possible to upload a JSP file to the server | High Known exploited | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-h3x4-894j-xpx5 Apache Tomcat's FORM authentication process has an Incorrect Authorization vulnerability | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-9xv2-5v5q-p794 Apache Tomcat's DIGEST authenticator has an Authentication Bypass by Capture-replay vulnerability | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
| GHSA-f525-44xv-f2qj Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation | Critical | Also affects org.apache.tomcat.embed:tomcat-embed-core |
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