{"id":"CVE-2023-44487","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-44487","generatedAt":"2026-10-31T10:23:41.703Z","title":"HTTP/2 Rapid Reset Attack Vulnerability","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.","published":"2023-10-10T14:15:11.000Z","lastModified":"2026-08-11T19:37:31.000Z","status":"Analyzed","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-400"],"affected":["siemens/simatic s7-1500 cpu 1518f-4 pn\\/dp mfp firmware","siemens/sinec ins","siemens/sinec nms","siemens/st7 scadaconnect","siemens/ruggedcom ape1808 firmware","siemens/simatic s7-1500 cpu 1518-4 pn\\/dp mfp firmware","siemens/siplus s7-1500 cpu 1518-4 pn\\/dp mfp firmware","ietf/http","nghttp2/nghttp2","netty/netty","envoyproxy/envoy","eclipse/jetty","caddyserver/caddy","golang/go","golang/http2","golang/networking","f5/big-ip access policy manager","f5/big-ip advanced firewall manager","f5/big-ip advanced web application firewall","f5/big-ip analytics","f5/big-ip application acceleration manager","f5/big-ip application security manager","f5/big-ip application visibility and reporting","f5/big-ip carrier-grade nat","f5/big-ip ddos hybrid defender","f5/big-ip domain name system","f5/big-ip fraud protection service","f5/big-ip global traffic manager","f5/big-ip link controller","f5/big-ip local traffic manager","f5/big-ip next","f5/big-ip next service proxy for kubernetes","f5/big-ip policy enforcement manager","f5/big-ip ssl orchestrator","f5/big-ip webaccelerator","f5/big-ip websafe","f5/nginx","f5/nginx ingress controller","f5/nginx plus","apache/tomcat","apple/swiftnio http\\/2","grpc/grpc","microsoft/.net","microsoft/asp.net core","microsoft/azure kubernetes service","microsoft/visual studio 2022","microsoft/windows 10 1607","microsoft/windows 10 1809","microsoft/windows 10 21h2","microsoft/windows 10 22h2","microsoft/windows 11 21h2","microsoft/windows 11 22h2","microsoft/windows server 2016","microsoft/windows server 2019","microsoft/windows server 2022","nodejs/node.js","microsoft/cbl-mariner","dena/h2o","facebook/proxygen","apache/apisix"],"epss":{"score":0.99999,"percentile":0.99998,"date":"2026-10-30","history":[]},"kev":{"listed":true,"dateAdded":"2023-10-10","dueDate":"2023-10-31","knownRansomwareCampaignUse":"Unknown","notes":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\nThis 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"},"exploits":{"count":1,"verified":false,"firstPublished":"2025-09-16","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":52426,"kind":"exploit","title":"HTTP/2 2.0 - Denial Of Service (DOS)","url":"https://www.exploit-db.com/exploits/52426","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/multiple/remote/52426.py","file":"exploits/multiple/remote/52426.py","published":"2025-09-16","added":"2025-09-16","updated":"2025-09-16","author":"Madhusudhan Rajappa","type":"remote","platform":"multiple","port":null,"verified":false,"codes":["CVE-2023-44487"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null}]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 31 October 2023). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://www.openwall.com/lists/oss-security/2023/10/10/6","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/10/7","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/13/4","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/13/9","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/18/4","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/18/8","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/19/6","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/20/8","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/security/cve/cve-2023-44487","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://arstechnica.com/security/2023/10/how-ddosers-used-the-http-2-protocol-to-deliver-attacks-of-unprecedented-size/","tags":["Press/Media Coverage","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://aws.amazon.com/security/security-bulletins/AWS-2023-011/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/","tags":["Technical Description","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/","tags":["Third Party Advisory","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.litespeedtech.com/2023/10/11/rapid-reset-http-2-vulnerablilty/","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack","tags":["Press/Media Coverage","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.vespa.ai/cve-2023-44487/","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://bugzilla.proxmox.com/show_bug.cgi?id=4988","tags":["Issue Tracking","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2242803","tags":["Issue Tracking","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://bugzilla.suse.com/show_bug.cgi?id=1216123","tags":["Issue Tracking","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9","tags":["Mailing List","Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/","tags":["Technical Description","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack","tags":["Technical Description","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://community.traefik.io/t/is-traefik-vulnerable-to-cve-2023-44487/20125","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"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","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://edg.io/lp/blog/resets-leaks-ddos-and-the-tale-of-a-hidden-cve","tags":["Broken Link"],"source":"cve@mitre.org"},{"url":"https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://gist.github.com/adulau/7c2bfb8e9cdbe4b35a5e131c66a0c088","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/Azure/AKS/issues/3947","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/Kong/kong/discussions/11741","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/advisories/GHSA-qppj-fm5r-hxr3","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/advisories/GHSA-vx74-f528-fxqg","tags":["Mitigation","Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/advisories/GHSA-xpw8-rcwv-8f8p","tags":["Patch","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/akka/akka-http/issues/4323","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/alibaba/tengine/issues/1872","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/apache/apisix/issues/10320","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/apache/httpd-site/pull/10","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/apache/httpd/blob/afcdbeebbff4b0c50ea26cdd16e178c0d1f24152/modules/http2/h2_mplx.c#L1101-L1113","tags":["Product"],"source":"cve@mitre.org"},{"url":"https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2","tags":["Product","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/apache/trafficserver/pull/10564","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/arkrwn/PoC/tree/main/CVE-2023-44487","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/bcdannyboy/CVE-2023-44487","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/caddyserver/caddy/issues/5877","tags":["Issue Tracking","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/caddyserver/caddy/releases/tag/v2.7.5","tags":["Release Notes","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/dotnet/announcements/issues/277","tags":["Issue Tracking","Mitigation","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73","tags":["Product","Release Notes"],"source":"cve@mitre.org"},{"url":"https://github.com/eclipse/jetty.project/issues/10679","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/envoyproxy/envoy/pull/30055","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/etcd-io/etcd/issues/16740","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/facebook/proxygen/pull/466","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/golang/go/issues/63417","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/grpc/grpc-go/pull/6703","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/grpc/grpc/releases/tag/v1.59.2","tags":["Mailing List"],"source":"cve@mitre.org"},{"url":"https://github.com/h2o/h2o/pull/3291","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/h2o/h2o/security/advisories/GHSA-2m7v-gc89-fjqf","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/haproxy/haproxy/issues/2312","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/icing/mod_h2/blob/0a864782af0a942aa2ad4ed960a6b32cd35bcf0a/mod_http2/README.md?plain=1#L239-L244","tags":["Product"],"source":"cve@mitre.org"},{"url":"https://github.com/junkurihara/rust-rpxy/issues/97","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/kazu-yamamoto/http2/commit/f61d41a502bd0f60eb24e1ce14edc7b6df6722a1","tags":["Patch"],"source":"cve@mitre.org"},{"url":"https://github.com/kazu-yamamoto/http2/issues/93","tags":["Issue Tracking"],"source":"cve@mitre.org"},{"url":"https://github.com/kubernetes/kubernetes/pull/121120","tags":["Issue Tracking","Patch"],"source":"cve@mitre.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-44487","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}