CVE-2024-30255

highpriority · attend · 71EPSS 0.878 · 100 %ileexploit · PoCDEEURUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

87.8% (100th) EPSS

CVSS 7.5 · high

Is it mine?

86 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-25

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.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.3–7.5

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.15.3mediumAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · FSTEC (BDU) RU

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · ENISA EU

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · security-advisories@github.comexploitability 3.9 · impact 1.4

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-390USCWE-390USCWE-400US

exploits (1)

Public proof-of-concept and weaponised exploit code.

blackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoCCVE-2024-30255 This repository contains a proof-of-concept (PoC) Python script to demonstrate the CPU exhaustion vulnerability in Envoy caused by a flood of CONTINUATION frames.PoC · poc_in_github

affected products (86)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Arista EOSall versionscert_bundDEcpe:/o:arista:arista_eos:-
Broadcom Brocade SANnavall versionscert_bundDEcpe:/a:broadcom:brocade_sannav:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Dell NetWorkerall versionscert_bundDEcpe:/a:dell:networker:-
Dell integrated Dell Remote Access Controller 10all versionscert_bundDEcpe:/h:dell:idrac:10
EMC Avamarall versionscert_bundDEcpe:/a:emc:avamar:-
Fedora Linuxall versionscert_bundDEcpe:/o:fedoraproject:fedora:-
Gentoo Linuxall versionscert_bundDEcpe:/o:gentoo:linux:-
IBM App Connect Enterpriseall versionscert_bundDEcpe:/a:ibm:app_connect_enterprise:-
IBM FlashSystemall versionscert_bundDEcpe:/a:ibm:flashsystem:-
IBM MQ Operatorall versionscert_bundDEcpe:/a:ibm:mq:operator
IBM Power Hardware Management Console V10all versionscert_bundDEcpe:/a:ibm:hardware_management_console:v10
IBM SAN Volume Controllerall versionscert_bundDEcpe:/a:ibm:san_volume_controller:-
IBM Storwizeall versionscert_bundDEcpe:/a:ibm:storwize:-
Open Source nghttp2all versionscert_bundDEcpe:/a:nghttp2:nghttp2:-
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
RESF Rocky Linuxall versionscert_bundDEcpe:/o:resf:rocky_linux:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Red Hat Enterprise Linux Advanced Cluster Security for Kubernetes 4all versionscert_bundDEcpe:/o:redhat:enterprise_linux:advanced_cluster_security_for_kubernetes_4

showing 20 of 86

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2024-0789HTTP/2: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2024-04-03csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstellen in verschiedenen http/2 Implementierungen ausnutzen, um einen Denial of Service Angriff durchzuführen.
BIT-envoy-2024-30255HTTP/2: CPU exhaustion due to CONTINUATION frame flood2024-04-06vendor · osvUS
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.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv cert_bund NVD CVE.org MITRE

published 2024-04-04modified 2026-06-17

references (10)

External citations — patches, advisories, analysis.

scry

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