CVE-2024-22019: Node.js HTTP Server DoS Vulnerability

CVE-2024-22019 Overview

A vulnerability in Node.js HTTP servers allows an attacker to send a specially crafted HTTP request with chunked encoding, leading to resource exhaustion and denial of service (DoS). The server reads an unbounded number of bytes from a single connection, exploiting the lack of limitations on chunk extension bytes. The issue can cause CPU and network bandwidth exhaustion, bypassing standard safeguards like timeouts and body size limits.

Critical Impact

Attackers can exhaust server resources through a single malicious HTTP connection, causing complete service unavailability while bypassing traditional DoS protections.

Affected Products

• Node.js (LTS and Current versions)
• NetApp Astra Control Center

Discovery Timeline

• 2024-02-20 - CVE CVE-2024-22019 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2024-22019

Vulnerability Analysis

This vulnerability targets the HTTP chunked transfer encoding implementation in Node.js servers. The flaw exists in how the server handles chunk extension bytes during HTTP request processing. When processing chunked transfer encoding, the server fails to impose adequate limits on the amount of data it reads from chunk extensions, allowing an attacker to force the server to consume unbounded resources from a single connection.

The vulnerability is particularly concerning because it circumvents standard DoS protections that administrators typically rely upon. Request timeouts and body size limits, which are common safeguards against resource exhaustion attacks, do not apply to chunk extension data. This creates a gap in the security model where a malicious client can maintain a persistent connection while continuously sending chunk extension data, exhausting both CPU cycles and network bandwidth.

Root Cause

The root cause is classified as CWE-404 (Improper Resource Shutdown or Release). The Node.js HTTP parser does not properly limit or release resources when handling chunk extension bytes in HTTP chunked transfer encoding. The absence of bounds checking on the chunk extension field allows attackers to send arbitrarily large amounts of extension data without triggering the server's protective mechanisms.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker establishes a standard HTTP connection to a vulnerable Node.js server and sends an HTTP request using chunked transfer encoding. By crafting the request with excessively large chunk extension data, the attacker forces the server to continuously read and process this data. Since chunk extensions are not subject to the same limits as the request body, the server will continue consuming resources until either the connection is closed or the server becomes unresponsive.

The attack is effective because:

• It requires only a single connection to cause significant resource consumption
• Standard HTTP timeout mechanisms do not apply to ongoing chunk processing
• Body size limits do not account for chunk extension data
• The server cannot easily distinguish malicious chunk extensions from legitimate traffic

Detection Methods for CVE-2024-22019

Indicators of Compromise

• Unusual CPU utilization spikes on Node.js server processes
• Single connections maintaining open state for extended periods while transferring minimal actual payload data
• Network traffic analysis showing HTTP requests with abnormally large chunk extension fields
• Server logs indicating slow or stalled request processing without corresponding large payloads

Detection Strategies

• Monitor Node.js process resource consumption for anomalies, particularly sustained high CPU usage correlating with low request completion rates
• Implement network-level inspection for HTTP chunked encoding requests with excessive extension data
• Deploy application performance monitoring to detect requests that consume disproportionate server resources
• Review web server access logs for connections with unusual duration or data transfer patterns

Monitoring Recommendations

• Configure alerting on Node.js process CPU and memory thresholds
• Implement connection tracking to identify long-lived HTTP connections with minimal throughput
• Enable verbose logging on load balancers or reverse proxies to capture chunked encoding anomalies
• Deploy real-time network traffic analysis to detect potential exploitation attempts

How to Mitigate CVE-2024-22019

Immediate Actions Required

• Update Node.js to a patched version that addresses the chunk extension handling vulnerability
• Deploy a reverse proxy or web application firewall (WAF) configured to inspect and limit chunked transfer encoding requests
• Implement connection-level rate limiting to restrict resource consumption per client
• Review and harden server timeout configurations at the infrastructure level

Patch Information

Node.js has released security updates to address this vulnerability. Administrators should update to the latest patched versions of their respective Node.js release lines (LTS and Current). Additional vendor advisories are available from NetApp Security Advisory NTAP-20240315-0004 for Astra Control Center deployments. The Debian LTS Announcement provides guidance for Debian-based systems. Technical details of the vulnerability can be found in HackerOne Report #2233486.

Workarounds

• Place Node.js servers behind a reverse proxy (such as nginx or HAProxy) that can filter or limit chunked encoding requests
• Implement network-level controls to limit connection duration and data rates per source IP
• Deploy load balancers configured to detect and terminate abnormally long-running connections
• Consider application-level middleware that validates chunked encoding requests before they reach the Node.js HTTP parser

# Example nginx configuration to limit chunk size and connection duration
# Add to your nginx server block

client_body_timeout 30s;
client_header_timeout 30s;
client_max_body_size 10m;
limit_conn_zone $binary_remote_addr zone=conn_limit:10m;
limit_conn conn_limit 10;
limit_req_zone $binary_remote_addr zone=req_limit:10m rate=10r/s;
limit_req zone=req_limit burst=20 nodelay;