CVE-2024-30255
HTTP/2: CPU exhaustion due to CONTINUATION frame flood
Description
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.
INFO
Published Date :
April 4, 2024, 8:15 p.m.
Last Modified :
Sept. 4, 2025, 7:41 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Run 'dnf update ecs-service-connect-agent --releasever 2023.5.20240624' to update your system.
Public PoC/Exploit Available at Github
CVE-2024-30255 has a 6 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2024-30255.
| URL | Resource |
|---|---|
| http://www.openwall.com/lists/oss-security/2024/04/03/16 | Mailing List Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2024/04/05/3 | Mailing List |
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm | Patch Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2024/04/03/16 | Mailing List Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2024/04/05/3 | Mailing List |
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm | Patch Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2024-30255 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2024-30255
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
CVE-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.
Python
Proof of concept (PoC) for CVE-2024-27316 (tested), CVE-2024-30255 (untested), CVE-2024-31309 (untested), CVE-2024-28182 (untested), CVE-2024-2653 (untested) and CVE-2024-27919 (untested)
cve-2024-2653 cve-2024-27316 cve-2024-27919 cve-2024-28182 cve-2024-30255 cve-2024-31309
Go
A proof of concept for CVE-2024-27316 (tested), CVE-2024-31309 (untested), CVE-2024-30255 (untested), CVE-2024-28182 (untested), CVE-2024-2653 (untested) and CVE-2024-27919 (untested)
PoC HTTP/2 Continuation Flood DOS Attack
Python
Proof of Concept: HTTP/2 CONTINUATION Flood
http2 poc proof-of-concept vulnerability http2-continuation-flood
Python Dockerfile Go
This repo showcases a proof of concept for HTTP/2 CONTINUATION Flood vulnerabilities, allowing testing and understanding of potential DoS attacks on servers due to protocol implementation flaws. Includes code, documentation, and CVE mapping.
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2024-30255 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2024-30255 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 04, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions up to (excluding) 1.26.8 *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.27.0 up to (excluding) 1.27.4 *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.28.0 up to (excluding) 1.28.2 *cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* versions from (including) 1.29.0 up to (excluding) 1.29.3 Added Reference Type CVE: http://www.openwall.com/lists/oss-security/2024/04/03/16 Types: Mailing List, Third Party Advisory Added Reference Type GitHub, Inc.: http://www.openwall.com/lists/oss-security/2024/04/03/16 Types: Mailing List, Third Party Advisory Added Reference Type CVE: http://www.openwall.com/lists/oss-security/2024/04/05/3 Types: Mailing List Added Reference Type GitHub, Inc.: http://www.openwall.com/lists/oss-security/2024/04/05/3 Types: Mailing List Added Reference Type CVE: https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm Types: Patch, Third Party Advisory Added Reference Type GitHub, Inc.: https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm Types: Patch, Third Party Advisory -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2024/04/03/16 Added Reference http://www.openwall.com/lists/oss-security/2024/04/05/3 Added Reference https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
May. 01, 2024
Action Type Old Value New Value Added Reference GitHub, Inc. http://www.openwall.com/lists/oss-security/2024/04/05/3 [No types assigned] Added Reference GitHub, Inc. http://www.openwall.com/lists/oss-security/2024/04/03/16 [No types assigned] -
CVE Received by [email protected]
Apr. 04, 2024
Action Type Old Value New Value Added Description 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. Added Reference GitHub, Inc. https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm [No types assigned] Added CWE GitHub, Inc. CWE-390 Added CVSS V3.1 GitHub, Inc. AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L