How do I fix CVE-2023-44487?

Update nginx to 1.25.3+, Apache to 2.4.58+, and apply all vendor patches. Enable Cloudflare or CDN-level DDoS protection. Set http2_max_concurrent_streams to a low value (e.g., 128) in nginx. Implement rate limiting on HTTP/2 connections at the edge. Monitor for traffic spikes and RESET_STREAM frames. Consider disabling HTTP/2 on exposed endpoints if not required.

highCVSS 7.5/10·Published: 2023-10-10·HTTP/2 servers (nginx, Apache, Node.js, Go, AWS, Cloudflare)

How to fix CVE-2023-44487 – Step-by-Step Guide

CVE-2023-44487, known as the HTTP/2 Rapid Reset DDoS Attack, is a critical vulnerability impacting virtually all HTTP/2 server implementations. This high-severity flaw enables highly efficient denial-of-service attacks. Immediate patching is essential to protect your infrastructure.

CVE ID

CVE-2023-44487

Severity

HIGH

CVSS Score

7.5/10

Affected

HTTP/2 servers (nginx, Apache, Node.js, Go, AWS, Cloudflare)

What is HTTP/2 Rapid Reset DDoS Attack?

The HTTP/2 Rapid Reset Attack exploits the protocol's stream cancellation feature. Attackers rapidly open and reset thousands of streams within a single HTTP/2 connection. This overwhelms the server's processing capabilities, leading to resource exhaustion and denial of service with minimal attacker resources.

Affected Versions

All HTTP/2 server implementations (pre-patch)

Fixed In

Nginx 1.25.3+, nghttp2 1.57.0+, vendor-specific patches

Official References

Impact and Risks for your Infrastructure

This vulnerability enables extremely efficient DDoS attacks, allowing attackers to overwhelm servers with a fraction of normal traffic. Businesses face severe service disruptions, reputational damage, and potential financial losses due to unavailable services. Infrastructure stability is critically compromised.

http2ddosnginxhigh2023

Step-by-Step Mitigation Guide

Apply vendor-specific patches immediately. For Nginx, upgrade to version 1.25.3+ or 1.24.0+. For nghttp2, update to 1.57.0+. Verify the fix by ensuring your server reports the updated version numbers and monitoring for any unusual traffic patterns or resource spikes.

1Update nginx to 1.25.3+, Apache to 2.4.58+, and apply all vendor patches.
2Enable Cloudflare or CDN-level DDoS protection.
3Set http2_max_concurrent_streams to a low value (e.g., 128) in nginx.
4Implement rate limiting on HTTP/2 connections at the edge.
5Monitor for traffic spikes and RESET_STREAM frames.
6Consider disabling HTTP/2 on exposed endpoints if not required.

Frequently Asked Questions

What is the CVSS score for CVE-2023-44487?▼

CVE-2023-44487 has a CVSS score of 7.5/10 (high severity). This reflects a significant security risk that should be addressed promptly.

Which versions of HTTP/2 servers (nginx, Apache, Node.js, Go, AWS, Cloudflare) are affected?▼

Affected: All HTTP/2 server implementations (pre-patch). The vulnerability was fixed in: Nginx 1.25.3+, nghttp2 1.57.0+, vendor-specific patches.

How long does it take to fix CVE-2023-44487?▼

For most teams: 15–60 minutes to apply the patch, plus 15 minutes of post-patch verification. Complex multi-service environments may require 2–4 hours including staging validation.

Is CVE-2023-44487 being actively exploited?▼

Check the NVD entry and CISA KEV catalog for exploitation status. As a high-severity vulnerability, treat it as a priority remediation regardless of known exploitation status.

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This CVE fix guide is based on publicly available security advisories (NVD, vendor bulletins). Always test changes in a staging environment before applying to production. Verify against the official vendor advisory for the most up-to-date guidance.