CVE-2024-56337Network attack vector

Remote code execution via Default Servlet race

Published Dec 20, 2024 · Updated Nov 4, 2025

A TOCTOU race in affected Apache Tomcat releases allows remote attackers to execute code through the write-enabled Default Servlet. Concurrent read and upload requests for the same case-variant path bypass case-sensitivity checks, causing attacker-supplied content to be compiled as a JSP. Exploitation requires a case-insensitive file system, readonly=false, and an unsafe Java canonical-path cache setting; successful exploitation runs code with the Tomcat process privileges.

CVSS severity9.8
Critical
EPSS probability9.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A TOCTOU race in affected Apache Tomcat releases allows remote attackers to execute code through the write-enabled Default Servlet. Concurrent read and upload requests for the same case-variant path bypass case-sensitivity checks, causing attacker-supplied content to be compiled as a JSP. Exploitation requires a case-insensitive file system, readonly=false, and an unsafe Java canonical-path cache setting; successful exploitation runs code with the Tomcat process privileges.

The record

CVE
CVE-2024-56337
Published
Dec 20, 2024
Updated
Nov 4, 2025
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-367, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1.0-M1 <=10.1.33
  2. Affected versionversion=11.0.0-M1 <=11.0.1
  3. Affected versionversion=8.5.0 <=8.5.100
  4. Affected versionversion=9.0.0.M1 <=9.0.97

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.0-M1 <=10.1.33; version=11.0.0-M1 <=11.0.1; version=8.5.0 <=8.5.100; version=9.0.0.M1 <=9.0.97

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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