CVE-2023-44487
Act now ● On CISA KEV — actively exploited
Actively exploited — on the CISA KEV list.
CVSS base
7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS — probability of exploitation (30 days)
100.0%
100.0th percentile
CISA KEV
Listed
Added 2023-10-10 · patch by 2023-10-31
Weakness / dates
CWE-400
Published 2023-10-10 · modified 2026-08-11
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | N | None |
| Integrity | N | None |
| Availability | H | High |
Timeline
- 2023-10-10 — Published (NVD)
- 2023-10-10 — Added to CISA KEV (actively exploited)
- 2023-10-31 — CISA patch-by deadline
- 2026-08-11 — Last modified (NVD)
Description
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.
Affected
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
- https://blog.vespa.ai/cve-2023-44487/
- https://bugzilla.proxmox.com/show_bug.cgi?id=4988
- https://bugzilla.redhat.com/show_bug.cgi?id=2242803
- https://bugzilla.suse.com/show_bug.cgi?id=1216123
- https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9
- https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/
- https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack
- https://community.traefik.io/t/is-traefik-vulnerable-to-cve-2023-44487/20125
- https://discuss.hashicorp.com/t/hcsec-2023-32-vault-consul-and-boundary-affected-by-http-2-rapid-reset-denial-of-service-vulnerability-cve-2023-44487/59715
- https://edg.io/lp/blog/resets-leaks-ddos-and-the-tale-of-a-hidden-cve
- https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764
- https://gist.github.com/adulau/7c2bfb8e9cdbe4b35a5e131c66a0c088
- https://github.com/Azure/AKS/issues/3947
- https://github.com/Kong/kong/discussions/11741
- https://github.com/advisories/GHSA-qppj-fm5r-hxr3