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Full vulnerability report · 2024
CVE-2024-30255High confidence

HTTP/2: CPU exhaustion due to CONTINUATION frame flood

envoyproxy · envoy

5.3MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2024-30255 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityenvoy: HTTP/2 CPU exhaustion due to CONTINUATION frame flood
15 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • custom-metrics-autoscaler/custom-metrics-autoscaler-rhel8 as a component of Custom Metric Autoscaler operator for Red Hat Openshift
  • lvms4/topolvm-rhel8 as a component of Logical Volume Manager Storage
  • mta/mta-hub-rhel9 as a component of Migration Toolkit for Applications 6
  • openshift-serverless-1/eventing-mtping-rhel8 as a component of OpenShift Serverless
  • rhceph/rhceph-5-dashboard-rhel8 as a component of Red Hat Ceph Storage 5
  • rhceph/rhceph-6-dashboard-rhel9 as a component of Red Hat Ceph Storage 6
  • openshift-selinuxd-container as a component of Red Hat OpenShift Container Platform 4
  • openshift4/ose-contour-rhel8 as a component of Red Hat OpenShift Container Platform 4
  • ocs4/cephcsi-rhel8 as a component of Red Hat Openshift Container Storage 4
  • rhods/odh-ml-pipelines-cache-rhel8 as a component of Red Hat OpenShift Data Science (RHODS)
  • rhods/odh-operator-base-rhel8 as a component of Red Hat OpenShift Data Science (RHODS)
  • devspaces/devspaces-rhel8-operator as a component of Red Hat OpenShift Dev Spaces
Summary
A vulnerability was found in how Envoy Proxy implements the HTTP/2 codec. There are insufficient limitations placed on the amount of CONTINUATION frames that can be sent within a single stream. This issue could allow an unauthenticated remote attacker to send packets to vulnerable servers, which could use up compute resources to cause a Denial of Service.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2024-28182

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

What

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

Why

The product detects a specific error, but takes no actions to handle the error.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

Why

The product detects a specific error, but takes no actions to handle the error.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Detection of Error Condition Without Action → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-390 ↗

CWE-390: Detection of Error Condition Without Action. The product detects a specific error, but takes no actions to handle the error.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-390
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2024-0789HTTP/2: Mehrere Schwachstellen ermöglichen Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstellen in verschiedenen http/2 Implementierungen ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20240410Security Bulletin 10 Apr 2024

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Apr 2024, published on 10 April 2024. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0404Multiples vulnérabilités dans les produits Fortinet

d?id=CVE-2024-23667 Référence CVE CVE-2024-23668 https://www.cve.org/CVERecord?id=CVE-2024-23668 Référence CVE CVE-2024-23669 https://www.cve.org/CVERecord?id=CVE-2024-23669 Référence CVE CVE-2024-23670 https://www.cve.org/CVERecord?id=CVE-2024-23670 Référence CVE CVE-2024-24549 https://www.cve.org/CVERecord?id=CVE-2024-24549 Référence CVE CVE-2024-26007 https://www.cve.org/CVERecord?id=CVE-2024-26007 Référence CVE CVE-2024-27316 https://www.cve.org/CVERecord?id=CVE-2024-27316 Référence CVE CVE-2024-27983 https://www.cve.org/CVERecord?id=CVE-2024-27983 Référence CVE CVE-2024-28182 https://www.cve.org/CVERecord?id=CVE-2024-28182 Référence CVE CVE-2024-30255 https://www.cve.org/CVERecord?id=CVE-2024-30255 Référence CVE CVE-2024-31488 https://www.cve.org/CVERecord?id=CVE-2024-31488 Référence CVE CVE-2024-31491 https://www.cve.org/CVERecord?id=CVE-2024-31491 Référence CVE CVE-2024-31493 https://www.cve.org/CVERecord?id=CVE-2024-31493 Référence CVE CVE-2024-3302 https://www.cve.org/CVERecord?id=CVE-2024-3302 Gestion détaillée du document le 15 mai 2024 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Premier Ministre / Secrétariat Général de la Dé

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2024-027661Envoy Proxy の Envoy におけるエラー対応処理のないエラーの検出に関する脆弱性

Envoy Proxy の Envoy には、エラー対応処理のないエラーの検出に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 4 Apr 2024 · Last source change 4 Nov 2025, 18:30 UTC · CWE-390 · Detection of Error Condition Without Action

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2024-28182
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2024-28182↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2024-30255 · cve.blacktree.nl