CVE-2024-34750Network attack vector

Denial of service via HTTP/2 stream miscount

Published Jul 3, 2024 · Updated Nov 3, 2025

Denial of service in affected Apache Tomcat releases allows remote attackers to hold HTTP/2 connections open with excessive headers. Http2UpgradeHandler can decrement a rejected stream's active count more than once, driving the count below zero and selecting an infinite connection timeout. The server must expose HTTP/2; unauthenticated clients can retain connections that Tomcat should close, consuming availability resources.

CVSS severity7.5
High
EPSS probability4.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Apache Tomcat releases allows remote attackers to hold HTTP/2 connections open with excessive headers. Http2UpgradeHandler can decrement a rejected stream's active count more than once, driving the count below zero and selecting an infinite connection timeout. The server must expose HTTP/2; unauthenticated clients can retain connections that Tomcat should close, consuming availability resources.

The record

CVE
CVE-2024-34750
Published
Jul 3, 2024
Updated
Nov 3, 2025
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-400, CWE-755, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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 <=10.1.24
  2. Affected versionversion=10.1.0-M1 <=10.1.24
  3. Affected versionversion=11.0.0-m1 <=11.0.0-m20
  4. Affected versionversion=11.0.0-M1 <=11.0.0-M20
  5. Affected versionversion=8.5.0 <=8.5.100
  6. Affected versionversion=9.0.0-m1 <=9.0.89
  7. Affected versionversion=9.0.0-M1 <=9.0.89

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.0-m1 <=10.1.24; version=10.1.0-M1 <=10.1.24; version=11.0.0-m1 <=11.0.0-m20; version=11.0.0-M1 <=11.0.0-M20; version=8.5.0 <=8.5.100; version=9.0.0-m1 <=9.0.89; version=9.0.0-M1 <=9.0.89

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-400Uncontrolled Resource Consumption
CWE-755Improper Handling of Exceptional Conditions
T1499.002Endpoint Denial of Service: Service Exhaustion Flood

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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