CVE DATABASE / CVE-2023-44487
CVE-2023-44487
HTTP/2 Rapid Reset Attack Vulnerability
Confirmed exploited in the wild. Added 2023-10-10.
Federal remediation due 2023-10-31.
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.
Summary
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
CVSS 3.1 breakdown
| Base score | 7.5 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity | NONE |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Use our free CVE Lookup tool for the latest NVD record, or browse the full CISA KEV catalog.
References
- http://www.openwall.com/lists/oss-security/2023/10/10/6
- http://www.openwall.com/lists/oss-security/2023/10/10/7
- http://www.openwall.com/lists/oss-security/2023/10/13/4
- http://www.openwall.com/lists/oss-security/2023/10/13/9
- http://www.openwall.com/lists/oss-security/2023/10/18/4
- http://www.openwall.com/lists/oss-security/2023/10/18/8
- http://www.openwall.com/lists/oss-security/2023/10/19/6
- http://www.openwall.com/lists/oss-security/2023/10/20/8
- https://access.redhat.com/security/cve/cve-2023-44487
- https://arstechnica.com/security/2023/10/how-ddosers-used-the-http-2-protocol-to-deliver-attacks-of-unprecedented-size/
- https://aws.amazon.com/security/security-bulletins/AWS-2023-011/
- https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/
- https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/
- https://blog.litespeedtech.com/2023/10/11/rapid-reset-http-2-vulnerablilty/
- https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack
Data: NIST NVD + CISA KEV. NVD last modified 2026-05-12. Always verify against the vendor advisory before acting.