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IETF · HTTP/2

CVE-2023-44487

HTTP/2 Rapid Reset Attack Vulnerability

CISA KEV record

CISA date added
2023-10-10
CISA due date
2023-10-31
Known ransomware use
Unknown

NVD risk context

7.5 HIGH

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

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Attack vector
Network
The vulnerable service can be reached remotely over a network.
Attack complexity
Low
Exploitation does not require unusual conditions beyond normal attacker control.
Privileges required
None
The attacker does not need an existing account or privileges.
User interaction
None
No action by another user is required.

Description

HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).

Required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

Other NVD references (118)

MITRE CWE context

CWE classification

NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published
Oct 10, 2023, 02:15 PM UTC
When NVD first published this CVE record.
NVD last updated
Jun 17, 2026, 06:27 AM UTC
When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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CISA notes

This vulnerability affects a common open-source component, third-party library, or protocol used by different products. For more information, please see: HTTP/2 Rapid Reset Vulnerability, CVE-2023-44487 | CISA: https://www.cisa.gov/news-events/alerts/2023/10/10/http2-rapid-reset-vulnerability-cve-2023-44487; https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/; https://nvd.nist.gov/vuln/detail/CVE-2023-44487