CVE-2025-52434: Apache Tomcat race condition in APR/Native connector

CVE-2025-52434 · Severity: high · CVSS 7.5 · Published 2025-07-10

Apache Tomcat is a widely used web server for hosting Java applications. A flaw in how it handles specific network connections can allow an attacker to exhaust the server's resources, potentially causing the website or application to become unavailable to legitimate users. This issue is most prominent when the server is configured to use the APR/Native connector and handles HTTP/2 traffic.

Technologies: Apache Tomcat, org.apache.tomcat:tomcat-coyote (Maven), org.apache.tomcat.embed:tomcat-embed-core (Maven). Vendors: Apache, Maven.

Quick answers

Is CVE-2025-52434 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-52434 being exploited in the wild.
How severe is CVE-2025-52434?
High severity, with a CVSS score of 7.5, published 10 July 2025.
Which products and versions are affected?
Apache Tomcat 9.0.0.M1 through 9.0.106, 8.5.0 through 8.5.100; org.apache.tomcat:tomcat-coyote (Maven) ECOSYSTEM:introduced=9.0.0.M1,fixed=9.0.107; org.apache.tomcat.embed:tomcat-embed-core (Maven) ECOSYSTEM:introduced=9.0.0.M1,fixed=9.0.107.
Is there a fix for CVE-2025-52434?
Yes. org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.107 or later; org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.107 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-52434 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2025-52434?
Check whether you run Apache Tomcat, org.apache.tomcat:tomcat-coyote (Maven) or org.apache.tomcat.embed:tomcat-embed-core (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.107 or later
    # set org.apache.tomcat:tomcat-coyote to 9.0.107 in your pom.xml or build.gradle
  • org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.107 or later
    # set org.apache.tomcat.embed:tomcat-embed-core to 9.0.107 in your pom.xml or build.gradle

Technical details

A race condition exists in Apache Tomcat's APR/Native connector due to improper synchronization when handling shared resources. The vulnerability is triggered during the concurrent execution of connection tasks, specifically when a client initiates the closure of an HTTP/2 connection. An unauthenticated remote attacker can exploit this to cause resource exhaustion, leading to a denial-of-service (DoS) condition. The issue affects Tomcat versions 9.0.0.M1 through 9.0.106 and 8.5.0 through 8.5.100. Users are advised to upgrade to version 9.0.107 or later.

Affected products

  • Apache Tomcat 9.0.0.M1 through 9.0.106, 8.5.0 through 8.5.100

Identifiers

  • CVE-2025-52434
  • GHSA-4j3c-42xv-3f84

Timeline

  • 2025-07-10: disclosed
  • 2025-07-10: advisory

References

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