dbcve.org
TomcatWeb server / proxy · Apache

CVE-2024-24549

HIGH · 7.5 CVSS v3.1 Published 2024-03-13
Fix available
A fix is available. Upgrade to 8.5.99 / 9.0.86 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
Denial of Service due to improper input validation vulnerability for HTTP/2 requests in Apache Tomcat. When processing an HTTP/2 request, if the request exceeded any of the configured limits for headers, the associated HTTP/2 stream was not reset until after all of the headers had been processed.This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.0-M16, from 10.1.0-M1 through 10.1.18, from 9.0.0-M1 through 9.0.85, from 8.5.0 through 8.5.98. Other, older, EOL versions may also be affected. Users are recommended to upgrade to version 11.0.0-M17, 10.1.19, 9.0.86 or 8.5.99 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's HTTP/2 implementation does not reset the stream immediately when header limits are exceeded. Instead, the server continues processing all headers before resetting, allowing malicious HTTP/2 requests with excessive headers to consume server resources and cause denial of service.

MitigationUpgrade to Apache Tomcat 11.0.0-M17, 10.1.19, 9.0.86, or 8.5.99 which fixes the issue. Alternatively, implement HTTP/2 request size limiting at a reverse proxy or load balancer in front of Tomcat.

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:>= 8.5.0, < 8.5.99>= 9.0.0, < 9.0.86>= 10.1.0, < 10.1.19= 11.0.0
Debian LinuxOperating system
Affected:= 10.0
FedoraOperating system
Affected:= 39= 40

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 Tomcat installation and version
    Check the Tomcat version by running: ls -la $CATALINA_HOME/lib/catalina.jar and reading the JAR manifest, or check the server info from startup logs (grep -i 'server version' catalina.out). On Debian/Fedora, use: dpkg -l | grep tomcat or rpm -qa | grep tomcat
    Affected if The installed version falls within 8.5.0 to 8.5.98, 9.0.0 to 9.0.85, 10.1.0 to 10.1.18, or is exactly 11.0.0
  2. Locate the server.xml configuration file
    Find server.xml in the Tomcat conf directory (typically $CATALINA_HOME/conf/server.xml or /etc/tomcat*/server.xml on packaged installations)
    Affected if File exists and contains HTTP/2 connector configuration
  3. Verify HTTP/2 protocol is enabled
    Search server.xml for HTTP/2 connector configuration: grep -E '(upgradeProtocol|h2|h2c|http2)' $CATALINA_HOME/conf/server.xml or view the connector elements with protocol="h2" or upgradeProtocol="org.apache.coyote.http2.Http2Protocol"
    Affected if An HTTP/2 upgrade protocol or HTTP/2 protocol is configured on any connector (the vulnerability only applies when HTTP/2 is actively enabled)
  4. Confirm header limit settings are at default
    Check server.xml for any custom maxHeaderCount or maxHttpHeaderSize settings in the connector element; also check conf/catalina.properties for related settings. Default limits are typically maxHeaderCount=200 or higher
    Affected if Header limits remain at default values (no custom maxHeaderCount configured) - this means the excessive header DoS can fully exploit the vulnerability

A system is affected if it runs a vulnerable Tomcat version (8.5.x before 8.5.99, 9.0.x before 9.0.86, 10.1.x before 10.1.19, or 11.0.0) AND has HTTP/2 protocol enabled in server.xml connector configuration, allowing attackers to send requests with headers exceeding limits to exhaust server resources before stream reset occurs.

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 8.5.99 / 9.0.86 / 10.1.19 or later
Fixed in 8.5.999.0.8610.1.19
Interim mitigation

Upgrade to Apache Tomcat 11.0.0-M17, 10.1.19, 9.0.86, or 8.5.99 which fixes the issue. Alternatively, implement HTTP/2 request size limiting at a reverse proxy or load balancer in front of Tomcat.

Recommended fix High confidence

8.5.99, 9.0.86, 10.1.19, or 11.0.0-M17 (depending on your major version)

  1. 1. Backup your current Tomcat installation and all configuration files
  2. 2. Stop the Tomcat service to ensure no active connections during upgrade
  3. 3. Download the appropriate fixed version for your installation: 8.5.99, 9.0.86, 10.1.19, or 11.0.0-M17 from the official Apache Tomcat mirrors
  4. 4. Extract the new Tomcat version to a temporary location
  5. 5. Copy the new Tomcat binaries over the existing installation, or install fresh and migrate configurations
  6. 6. Ensure your server.xml and other configuration files are compatible with the new version
  7. 7. Verify that your custom connectors, especially HTTP/2 configurations, are properly set
  8. 8. Start the Tomcat service and verify the server starts successfully
Caveat Minor version upgrades within the same major version typically have minimal breaking changes, but review the release notes for any deprecated features or configuration changes

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

Fix this in Tomcat Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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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-2024-24549 in production — separate from our analysis above.

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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