CVE-2024-4437Network attack vector

Service interruption via HTTP/2 header cache exhaustion

Published May 8, 2024 · Updated Nov 20, 2025

Resource exhaustion in Red Hat OpenStack products allows remote attackers to interrupt etcd service via crafted HTTP/2 requests. The bundled etcd binary uses a vulnerable golang.org/x/net/http2 canonicalHeader cache that retains attacker-chosen header names without a memory bound. An unauthenticated client must reach etcd's HTTP/2 listener; repeated unique headers drive unbounded memory growth and can interrupt service availability.

CVSS severity7.5
High
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Red Hat OpenStack products allows remote attackers to interrupt etcd service via crafted HTTP/2 requests. The bundled etcd binary uses a vulnerable golang.org/x/net/http2 canonicalHeader cache that retains attacker-chosen header names without a memory bound. An unauthenticated client must reach etcd's HTTP/2 listener; repeated unique headers drive unbounded memory growth and can interrupt service availability.

The record

CVE
CVE-2024-4437
Published
May 8, 2024
Updated
Nov 20, 2025
Vendor
Red Hat
Product
Red Hat OpenStack Platform
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat OpenStack PlatformAffected versions are unavailable in this record.
Red Hat · Red Hat OpenStack Services on OpenShiftAffected versions are unavailable in this record.

Published CVSS scores

7.5Red HatCVSS: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
T1499.003Application 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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