--- 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 update' - 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 - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VHUHTSXLXGXS7JYKBXTA3VINUPHTNGVU/ label: FEDORA-2023-1caffb88af - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSRDIV77HNKUSM7SJC5BKE5JSHLHU2NK/ label: FEDORA-2023-3f70b8d406 - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3N4NJ7FR4X4FPZUGNTQAPSTVB2HB2Y4A/ label: FEDORA-2023-7b52921cae - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZB43REMKRQR62NJEI7I5NQ4FSXNLBKRT/ label: FEDORA-2023-7934802344 - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HT7T2R4MQKLIF4ODV4BDLPARWFPCJ5CZ/ label: FEDORA-2023-dbe64661af - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XFOIBB4YFICHDM7IBOP7PWXW3FX4HLL2/ label: FEDORA-2023-822aab0a5a - url: 'https://lists.debian.org/debian-lts-announce/2023/11/msg00001.html' label: >- [debian-lts-announce] 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' --- ## Overview 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. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.