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TomcatWeb server / proxy · Apache

CVE-2025-52520

HIGH · 7.5 CVSS v3.1 Published 2025-07-10
Fix available
A fix is available. Upgrade to 9.0.107 / 10.1.43 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
For some unlikely configurations of multipart upload, an Integer Overflow vulnerability in Apache Tomcat could lead to a DoS via bypassing of size limits. 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, 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache Tomcat contains an integer overflow vulnerability in its multipart upload handling that allows attackers to bypass configured size limits, potentially enabling denial of service through excessive resource consumption when uploading oversized files.

MitigationUpgrade Apache Tomcat to version 11.0.9, 10.1.43, or 9.0.107 to patch the integer overflow in multipart upload size limit validation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
TomcatWeb server / proxy
Affected:>= 9.0.0, < 9.0.107>= 10.1.0, < 10.1.43>= 11.0.0, < 11.0.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Apache Tomcat version
    Check the release notes or the serverinfo.properties file in the Tomcat lib directory, or look at the startup logs which display the version number on launch
    Affected if The installed version is 9.0.0 through 9.0.106, 10.1.0 through 10.1.42, or 11.0.0 through 11.0.8
  2. Determine if multipart request handling is in use
    Review your web application configuration and code for multipart file upload functionality, typically enabled via the multipart-config element in servlet definitions or through frameworks that handle file uploads
    Affected if Multipart file uploads are processed by the Tomcat server
  3. Check if size limits are configured for multipart requests
    Inspect the web.xml or the application's servlet configuration for maxFileSize, maxRequestSize, or fileSizeThreshold parameters within the multipart-config element
    Affected if Multipart size limits are defined but the integer overflow can bypass them
  4. Verify Tomcat is handling requests directly
    Confirm that the server is not behind a reverse proxy or frontend that enforces its own upload size limits before requests reach Tomcat
    Affected if Tomcat directly processes multipart uploads without upstream size enforcement

You are affected if your Tomcat version falls within the vulnerable ranges and your application processes multipart file uploads that rely on Tomcat's size limits for protection.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.0.107 / 10.1.43 / 11.0.9 or later
Fixed in 9.0.10710.1.4311.0.9
Interim mitigation

Upgrade Apache Tomcat to version 11.0.9, 10.1.43, or 9.0.107 to patch the integer overflow in multipart upload size limit validation.

Recommended fix High confidence

Tomcat 9.0.107 (for 9.0.x), Tomcat 10.1.43 (for 10.1.x), or Tomcat 11.0.9 (for 11.x)

  1. 1. Identify the currently running Apache Tomcat version using bin/version.sh or by checking the server logs
  2. 2. Determine which major version branch you are using (9.x, 10.1.x, or 11.x)
  3. 3. Download the appropriate fixed release: Tomcat 9.0.107, 10.1.43, or 11.0.9 from the Apache Tomcat downloads page (tomcat.apache.org)
  4. 4. Stop the Tomcat server gracefully
  5. 5. Back up the existing Tomcat installation including conf/ directory and any custom configurations
  6. 6. Extract the new version to the target installation directory
  7. 7. Restore custom configurations from the backup to the new conf/ directory
  8. 8. Start the Tomcat server and verify the application functions correctly
Caveat Standard minor version upgrade - review release notes for any configuration changes between versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tomcat Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-52520 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data