CVE-2023-44487
HIGHCISA KEVEPSS 100th pctlDescription
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 v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
HTTP/2 Rapid Reset Attack Vulnerability
HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Remediation due: 2023-10-31
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
- https://github.com/advisories/GHSA-vx74-f528-fxqg
- https://github.com/advisories/GHSA-xpw8-rcwv-8f8p
- https://github.com/akka/akka-http/issues/4323
- https://github.com/alibaba/tengine/issues/1872
- https://github.com/apache/apisix/issues/10320
- https://github.com/apache/httpd-site/pull/10
- https://github.com/apache/httpd/blob/afcdbeebbff4b0c50ea26cdd16e178c0d1f24152/modules/http2/h2_mplx.c#L1101-L1113
- https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2
- https://github.com/apache/trafficserver/pull/10564
- https://github.com/arkrwn/PoC/tree/main/CVE-2023-44487
- https://github.com/bcdannyboy/CVE-2023-44487
- https://github.com/caddyserver/caddy/issues/5877
- https://github.com/caddyserver/caddy/releases/tag/v2.7.5
- https://github.com/dotnet/announcements/issues/277
- https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73
- https://github.com/eclipse/jetty.project/issues/10679
- https://github.com/envoyproxy/envoy/pull/30055
- https://github.com/etcd-io/etcd/issues/16740
- https://github.com/facebook/proxygen/pull/466
- https://github.com/golang/go/issues/63417
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-12.