{"id":"CVE-2023-44487","title":"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.","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.","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"adp","ssvc":{"exploitation":"active","automatable":"yes","technicalImpact":"partial","timestamp":"2024-07-23T20:34:21.334116Z"},"exploited":true,"exploitAvailable":true,"published":"2023-10-10","updated":"2026-10-14","sourceUpdated":"2026-10-14T23:51:51.782Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-44487","references":[{"url":"https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73"},{"url":"https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/"},{"url":"https://aws.amazon.com/security/security-bulletins/AWS-2023-011/"},{"url":"https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack"},{"url":"https://www.nginx.com/blog/http-2-rapid-reset-attack-impacting-f5-nginx-products/"},{"url":"https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/"},{"url":"https://news.ycombinator.com/item?id=37831062"},{"url":"https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/"},{"url":"https://www.phoronix.com/news/HTTP2-Rapid-Reset-Attack"},{"url":"https://github.com/envoyproxy/envoy/pull/30055"},{"url":"https://github.com/haproxy/haproxy/issues/2312"},{"url":"https://github.com/eclipse/jetty.project/issues/10679"},{"url":"https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764"},{"url":"https://github.com/nghttp2/nghttp2/pull/1961"},{"url":"https://github.com/netty/netty/commit/58f75f665aa81a8cbcf6ffa74820042a285c5e61"},{"url":"https://github.com/alibaba/tengine/issues/1872"},{"url":"https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2"},{"url":"https://news.ycombinator.com/item?id=37830987"},{"url":"https://news.ycombinator.com/item?id=37830998"},{"url":"https://github.com/caddyserver/caddy/issues/5877"},{"url":"https://www.bleepingcomputer.com/news/security/new-http-2-rapid-reset-zero-day-attack-breaks-ddos-records/"},{"url":"https://github.com/bcdannyboy/CVE-2023-44487"},{"url":"https://github.com/grpc/grpc-go/pull/6703"},{"url":"https://github.com/icing/mod_h2/blob/0a864782af0a942aa2ad4ed960a6b32cd35bcf0a/mod_http2/README.md?plain=1#L239-L244"},{"url":"https://github.com/nghttp2/nghttp2/releases/tag/v1.57.0"},{"url":"https://mailman.nginx.org/pipermail/nginx-devel/2023-October/S36Q5HBXR7CAIMPLLPRSSSYR4PCMWILK.html"},{"url":"https://my.f5.com/manage/s/article/K000137106"},{"url":"https://msrc.microsoft.com/blog/2023/10/microsoft-response-to-distributed-denial-of-service-ddos-attacks-against-http/2/"},{"url":"https://bugzilla.proxmox.com/show_bug.cgi?id=4988"},{"url":"https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/10/7","label":"[oss-security] 20231010 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/10/6","label":"[oss-security] 20231010 CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"https://seanmonstar.com/post/730794151136935936/hyper-http2-rapid-reset-unaffected"},{"url":"https://github.com/microsoft/CBL-Mariner/pull/6381"},{"url":"https://groups.google.com/g/golang-announce/c/iNNxDTCjZvo"},{"url":"https://github.com/facebook/proxygen/pull/466"},{"url":"https://gist.github.com/adulau/7c2bfb8e9cdbe4b35a5e131c66a0c088"},{"url":"https://github.com/micrictor/http2-rst-stream"},{"url":"https://edg.io/lp/blog/resets-leaks-ddos-and-the-tale-of-a-hidden-cve"},{"url":"https://openssf.org/blog/2023/10/10/http-2-rapid-reset-vulnerability-highlights-need-for-rapid-response/"},{"url":"https://github.com/h2o/h2o/security/advisories/GHSA-2m7v-gc89-fjqf"},{"url":"https://github.com/h2o/h2o/pull/3291"},{"url":"https://github.com/nodejs/node/pull/50121"},{"url":"https://github.com/dotnet/announcements/issues/277"},{"url":"https://github.com/golang/go/issues/63417"},{"url":"https://github.com/advisories/GHSA-vx74-f528-fxqg"},{"url":"https://github.com/apache/trafficserver/pull/10564"},{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-44487"},{"url":"https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.14"},{"url":"https://lists.apache.org/thread/5py8h42mxfsn8l1wy6o41xwhsjlsd87q"},{"url":"https://www.openwall.com/lists/oss-security/2023/10/10/6"},{"url":"https://www.haproxy.com/blog/haproxy-is-not-affected-by-the-http-2-rapid-reset-attack-cve-2023-44487"},{"url":"https://github.com/opensearch-project/data-prepper/issues/3474"},{"url":"https://github.com/kubernetes/kubernetes/pull/121120"},{"url":"https://github.com/oqtane/oqtane.framework/discussions/3367"},{"url":"https://github.com/advisories/GHSA-xpw8-rcwv-8f8p"},{"url":"https://netty.io/news/2023/10/10/4-1-100-Final.html"},{"url":"https://www.cisa.gov/news-events/alerts/2023/10/10/http2-rapid-reset-vulnerability-cve-2023-44487"},{"url":"https://www.theregister.com/2023/10/10/http2_rapid_reset_zeroday/"},{"url":"https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack"},{"url":"https://news.ycombinator.com/item?id=37837043"},{"url":"https://github.com/kazu-yamamoto/http2/issues/93"},{"url":"https://martinthomson.github.io/h2-stream-limits/draft-thomson-httpbis-h2-stream-limits.html"},{"url":"https://github.com/kazu-yamamoto/http2/commit/f61d41a502bd0f60eb24e1ce14edc7b6df6722a1"},{"url":"https://github.com/apache/httpd/blob/afcdbeebbff4b0c50ea26cdd16e178c0d1f24152/modules/http2/h2_mplx.c#L1101-L1113"},{"url":"https://www.debian.org/security/2023/dsa-5522","label":"DSA-5522"},{"url":"https://www.debian.org/security/2023/dsa-5521","label":"DSA-5521"},{"url":"https://access.redhat.com/security/cve/cve-2023-44487"},{"url":"https://github.com/ninenines/cowboy/issues/1615"},{"url":"https://github.com/varnishcache/varnish-cache/issues/3996"},{"url":"https://github.com/tempesta-tech/tempesta/issues/1986"},{"url":"https://blog.vespa.ai/cve-2023-44487/"},{"url":"https://github.com/etcd-io/etcd/issues/16740"},{"url":"https://www.darkreading.com/cloud/internet-wide-zero-day-bug-fuels-largest-ever-ddos-event"},{"url":"https://istio.io/latest/news/security/istio-security-2023-004/"},{"url":"https://github.com/junkurihara/rust-rpxy/issues/97"},{"url":"https://bugzilla.suse.com/show_bug.cgi?id=1216123"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2242803"},{"url":"https://ubuntu.com/security/CVE-2023-44487"},{"url":"https://community.traefik.io/t/is-traefik-vulnerable-to-cve-2023-44487/20125"},{"url":"https://github.com/advisories/GHSA-qppj-fm5r-hxr3"},{"url":"https://github.com/apache/httpd-site/pull/10"},{"url":"https://github.com/projectcontour/contour/pull/5826"},{"url":"https://github.com/linkerd/website/pull/1695/commits/4b9c6836471bc8270ab48aae6fd2181bc73fd632"},{"url":"https://github.com/line/armeria/pull/5232"},{"url":"https://blog.litespeedtech.com/2023/10/11/rapid-reset-http-2-vulnerablilty/"},{"url":"https://security.paloaltonetworks.com/CVE-2023-44487"},{"url":"https://github.com/akka/akka-http/issues/4323"},{"url":"https://github.com/openresty/openresty/issues/930"},{"url":"https://github.com/apache/apisix/issues/10320"},{"url":"https://github.com/Azure/AKS/issues/3947"},{"url":"https://github.com/Kong/kong/discussions/11741"},{"url":"https://github.com/arkrwn/PoC/tree/main/CVE-2023-44487"},{"url":"https://www.netlify.com/blog/netlify-successfully-mitigates-cve-2023-44487/"},{"url":"https://github.com/caddyserver/caddy/releases/tag/v2.7.5"},{"url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00020.html","label":"[debian-lts-announce] 20231013 [SECURITY] [DLA 3617-1] tomcat9 security update"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/13/4","label":"[oss-security] 20231013 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/13/9","label":"[oss-security] 20231013 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"https://arstechnica.com/security/2023/10/how-ddosers-used-the-http-2-protocol-to-deliver-attacks-of-unprecedented-size/"},{"url":"https://lists.w3.org/Archives/Public/ietf-http-wg/2023OctDec/0025.html"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JMEXY22BFG5Q64HQCM5CK2Q7KDKVV4TY/","label":"FEDORA-2023-ed2642fd58"},{"url":"https://linkerd.io/2023/10/12/linkerd-cve-2023-44487/"},{"url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00023.html","label":"[debian-lts-announce] 20231016 [SECURITY] [DLA 3621-1] nghttp2 security update"},{"url":"https://security.netapp.com/advisory/ntap-20231016-0001/"},{"url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00024.html","label":"[debian-lts-announce] 20231016 [SECURITY] [DLA 3617-2] tomcat9 regression update"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/18/4","label":"[oss-security] 20231018 Vulnerability in Jenkins"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/18/8","label":"[oss-security] 20231018 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/19/6","label":"[oss-security] 20231019 CVE-2023-45802: Apache HTTP Server: HTTP/2 stream memory not reclaimed right away on RST"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZKQSIKIAT5TJ3WSLU3RDBQ35YX4GY4V3/","label":"FEDORA-2023-54fadada12"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JIZSEFC3YKCGABA2BZW6ZJRMDZJMB7PJ/","label":"FEDORA-2023-5ff7bf1dd8"},{"url":"http://www.openwall.com/lists/oss-security/2023/10/20/8","label":"[oss-security] 20231020 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WLPRQ5TWUQQXYWBJM7ECYDAIL2YVKIUH/","label":"FEDORA-2023-17efd3f2cd"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/E72T67UPDRXHIDLO3OROR25YAMN4GGW5/","label":"FEDORA-2023-d5030c983c"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BFQD3KUEMFBHPAPBGLWQC34L4OWL5HAZ/","label":"FEDORA-2023-0259c3f26f"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZLU6U2R2IC2K64NDPNMV55AUAO65MAF4/","label":"FEDORA-2023-2a9214af5f"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X6QXN4ORIVF6XBW4WWFE7VNPVC74S45Y/","label":"FEDORA-2023-e9c04d81c1"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LKYHSZQFDNR7RSA7LHVLLIAQMVYCUGBG/","label":"FEDORA-2023-f66fc0f62a"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FNA62Q767CFAFHBCDKYNPBMZWB7TWYVU/","label":"FEDORA-2023-4d2fd884ea"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LNMZJCDHGLJJLXO4OXWJMTVQRNWOC7UL/","label":"FEDORA-2023-b2c50535cb"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KSEGD2IWKNUO3DWY4KQGUQM5BISRWHQE/","label":"FEDORA-2023-fe53e13b5b"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CLB4TW7KALB3EEQWNWCN7OUIWWVWWCG2/","label":"FEDORA-2023-4bf641255e"},{"url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00045.html","label":"[debian-lts-announce] 20231030 [SECURITY] [DLA 3641-1] jetty9 security update"},{"url":"https://www.debian.org/security/2023/dsa-5540","label":"DSA-5540"},{"url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00047.html","label":"[debian-lts-announce] 20231031 [SECURITY] [DLA 3638-1] h2o security 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20231105 [SECURITY] [DLA 3645-1] trafficserver security update"},{"url":"https://www.debian.org/security/2023/dsa-5549","label":"DSA-5549"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2MBEPPC36UBVOZZNAXFHKLFGSLCMN5LI/","label":"FEDORA-2023-c0c6a91330"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WE2I52RHNNU42PX6NZ2RBUHSFFJ2LVZX/","label":"FEDORA-2023-492b7be466"},{"url":"https://www.debian.org/security/2023/dsa-5558","label":"DSA-5558"},{"url":"https://lists.debian.org/debian-lts-announce/2023/11/msg00012.html","label":"[debian-lts-announce] 20231119 [SECURITY] [DLA 3656-1] netty security update"},{"url":"https://security.gentoo.org/glsa/202311-09","label":"GLSA-202311-09"},{"url":"https://www.debian.org/security/2023/dsa-5570","label":"DSA-5570"},{"url":"https://security.netapp.com/advisory/ntap-20240426-0007/"},{"url":"https://security.netapp.com/advisory/ntap-20240621-0006/"},{"url":"https://security.netapp.com/advisory/ntap-20240621-0007/"},{"url":"https://github.com/grpc/grpc/releases/tag/v1.59.2"},{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http2-reset-d8Kf32vZ"}],"tags":["cve.org","in-the-wild","exploit-available","kev"],"epss":0.99999,"epssPercentile":0.99998,"kev":true,"kevDateAdded":"2023-10-10","kevDueDate":"2023-10-31","kevRansomware":false,"exploits":{"exploitdb":true,"github":26,"githubRepos":["https://github.com/bcdannyboy/CVE-2023-44487","https://github.com/imabee101/CVE-2023-44487","https://github.com/ByteHackr/CVE-2023-44487"],"checkedAt":"2026-10-27T16:41:17.788Z"},"zeroDay":true,"ingestedAt":"2026-10-15T04:46:37.295Z","slug":"CVE-2023-44487","body":"## Overview\n\nThe 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"abyssal","depthScore":86,"depthScoreParts":{"impact":41.3,"likelihood":20,"exploitation":25,"ransomware":0},"changes":[]}