🔐 CVE Alert

CVE-2023-44487

HIGH 7.5 ⚠️ CISA KEV
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th

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.

Vendor n/a
Product n/a
Published Oct 10, 2023
Last Updated Nov 4, 2025
⚠️ Actively Exploited — Act Now

Get instant alerts for n/a n/a

This vulnerability is actively exploited in the wild. Set up free real-time alerts so you're first to know about threats like CVE-2023-44487.

Get Free Alerts → Free · No credit card · 60 sec setup

Affected Versions

n/a / n/a
n/a

References

NVD ↗ CVE.org ↗ EPSS Data ↗
github.com: https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73 blog.cloudflare.com: https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/ aws.amazon.com: https://aws.amazon.com/security/security-bulletins/AWS-2023-011/ cloud.google.com: https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack nginx.com: https://www.nginx.com/blog/http-2-rapid-reset-attack-impacting-f5-nginx-products/ cloud.google.com: https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/ news.ycombinator.com: https://news.ycombinator.com/item?id=37831062 blog.cloudflare.com: https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/ phoronix.com: https://www.phoronix.com/news/HTTP2-Rapid-Reset-Attack github.com: https://github.com/envoyproxy/envoy/pull/30055 github.com: https://github.com/haproxy/haproxy/issues/2312 github.com: https://github.com/eclipse/jetty.project/issues/10679 forums.swift.org: https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764 github.com: https://github.com/nghttp2/nghttp2/pull/1961 github.com: https://github.com/netty/netty/commit/58f75f665aa81a8cbcf6ffa74820042a285c5e61 github.com: https://github.com/alibaba/tengine/issues/1872 github.com: https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2 news.ycombinator.com: https://news.ycombinator.com/item?id=37830987 news.ycombinator.com: https://news.ycombinator.com/item?id=37830998 github.com: https://github.com/caddyserver/caddy/issues/5877 bleepingcomputer.com: https://www.bleepingcomputer.com/news/security/new-http-2-rapid-reset-zero-day-attack-breaks-ddos-records/ github.com: https://github.com/bcdannyboy/CVE-2023-44487 github.com: https://github.com/grpc/grpc-go/pull/6703 github.com: https://github.com/icing/mod_h2/blob/0a864782af0a942aa2ad4ed960a6b32cd35bcf0a/mod_http2/README.md?plain=1#L239-L244 github.com: https://github.com/nghttp2/nghttp2/releases/tag/v1.57.0 mailman.nginx.org: https://mailman.nginx.org/pipermail/nginx-devel/2023-October/S36Q5HBXR7CAIMPLLPRSSSYR4PCMWILK.html my.f5.com: https://my.f5.com/manage/s/article/K000137106 msrc.microsoft.com: https://msrc.microsoft.com/blog/2023/10/microsoft-response-to-distributed-denial-of-service-ddos-attacks-against-http/2/ bugzilla.proxmox.com: https://bugzilla.proxmox.com/show_bug.cgi?id=4988 cgit.freebsd.org: https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9 openwall.com: http://www.openwall.com/lists/oss-security/2023/10/10/7 openwall.com: http://www.openwall.com/lists/oss-security/2023/10/10/6 seanmonstar.com: https://seanmonstar.com/post/730794151136935936/hyper-http2-rapid-reset-unaffected github.com: https://github.com/microsoft/CBL-Mariner/pull/6381 groups.google.com: https://groups.google.com/g/golang-announce/c/iNNxDTCjZvo github.com: https://github.com/facebook/proxygen/pull/466 gist.github.com: https://gist.github.com/adulau/7c2bfb8e9cdbe4b35a5e131c66a0c088 github.com: https://github.com/micrictor/http2-rst-stream edg.io: https://edg.io/lp/blog/resets-leaks-ddos-and-the-tale-of-a-hidden-cve openssf.org: https://openssf.org/blog/2023/10/10/http-2-rapid-reset-vulnerability-highlights-need-for-rapid-response/ github.com: https://github.com/h2o/h2o/security/advisories/GHSA-2m7v-gc89-fjqf github.com: https://github.com/h2o/h2o/pull/3291 github.com: https://github.com/nodejs/node/pull/50121 github.com: https://github.com/dotnet/announcements/issues/277 github.com: https://github.com/golang/go/issues/63417 github.com: https://github.com/advisories/GHSA-vx74-f528-fxqg github.com: https://github.com/apache/trafficserver/pull/10564 msrc.microsoft.com: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-44487 tomcat.apache.org: https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.14 lists.apache.org: https://lists.apache.org/thread/5py8h42mxfsn8l1wy6o41xwhsjlsd87q openwall.com: https://www.openwall.com/lists/oss-security/2023/10/10/6 haproxy.com: https://www.haproxy.com/blog/haproxy-is-not-affected-by-the-http-2-rapid-reset-attack-cve-2023-44487 github.com: https://github.com/opensearch-project/data-prepper/issues/3474 github.com: https://github.com/kubernetes/kubernetes/pull/121120 github.com: https://github.com/oqtane/oqtane.framework/discussions/3367 github.com: https://github.com/advisories/GHSA-xpw8-rcwv-8f8p netty.io: https://netty.io/news/2023/10/10/4-1-100-Final.html cisa.gov: https://www.cisa.gov/news-events/alerts/2023/10/10/http2-rapid-reset-vulnerability-cve-2023-44487 theregister.com: https://www.theregister.com/2023/10/10/http2_rapid_reset_zeroday/ blog.qualys.com: https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack news.ycombinator.com: https://news.ycombinator.com/item?id=37837043 github.com: https://github.com/kazu-yamamoto/http2/issues/93 martinthomson.github.io: https://martinthomson.github.io/h2-stream-limits/draft-thomson-httpbis-h2-stream-limits.html github.com: https://github.com/kazu-yamamoto/http2/commit/f61d41a502bd0f60eb24e1ce14edc7b6df6722a1 github.com: https://github.com/apache/httpd/blob/afcdbeebbff4b0c50ea26cdd16e178c0d1f24152/modules/http2/h2_mplx.c#L1101-L1113 debian.org: https://www.debian.org/security/2023/dsa-5522 debian.org: https://www.debian.org/security/2023/dsa-5521 access.redhat.com: https://access.redhat.com/security/cve/cve-2023-44487 github.com: https://github.com/ninenines/cowboy/issues/1615 github.com: https://github.com/varnishcache/varnish-cache/issues/3996 github.com: https://github.com/tempesta-tech/tempesta/issues/1986 blog.vespa.ai: https://blog.vespa.ai/cve-2023-44487/ github.com: https://github.com/etcd-io/etcd/issues/16740 darkreading.com: https://www.darkreading.com/cloud/internet-wide-zero-day-bug-fuels-largest-ever-ddos-event istio.io: https://istio.io/latest/news/security/istio-security-2023-004/ github.com: https://github.com/junkurihara/rust-rpxy/issues/97 bugzilla.suse.com: https://bugzilla.suse.com/show_bug.cgi?id=1216123 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2242803 ubuntu.com: https://ubuntu.com/security/CVE-2023-44487 community.traefik.io: https://community.traefik.io/t/is-traefik-vulnerable-to-cve-2023-44487/20125 github.com: https://github.com/advisories/GHSA-qppj-fm5r-hxr3 github.com: https://github.com/apache/httpd-site/pull/10 github.com: https://github.com/projectcontour/contour/pull/5826 github.com: https://github.com/linkerd/website/pull/1695/commits/4b9c6836471bc8270ab48aae6fd2181bc73fd632 github.com: https://github.com/line/armeria/pull/5232 blog.litespeedtech.com: https://blog.litespeedtech.com/2023/10/11/rapid-reset-http-2-vulnerablilty/ security.paloaltonetworks.com: https://security.paloaltonetworks.com/CVE-2023-44487 github.com: https://github.com/akka/akka-http/issues/4323 github.com: https://github.com/openresty/openresty/issues/930 github.com: https://github.com/apache/apisix/issues/10320 github.com: https://github.com/Azure/AKS/issues/3947 github.com: https://github.com/Kong/kong/discussions/11741 github.com: https://github.com/arkrwn/PoC/tree/main/CVE-2023-44487 netlify.com: https://www.netlify.com/blog/netlify-successfully-mitigates-cve-2023-44487/ github.com: https://github.com/caddyserver/caddy/releases/tag/v2.7.5 lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00020.html openwall.com: http://www.openwall.com/lists/oss-security/2023/10/13/4 openwall.com: http://www.openwall.com/lists/oss-security/2023/10/13/9 arstechnica.com: https://arstechnica.com/security/2023/10/how-ddosers-used-the-http-2-protocol-to-deliver-attacks-of-unprecedented-size/ lists.w3.org: https://lists.w3.org/Archives/Public/ietf-http-wg/2023OctDec/0025.html lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/JMEXY22BFG5Q64HQCM5CK2Q7KDKVV4TY/ linkerd.io: https://linkerd.io/2023/10/12/linkerd-cve-2023-44487/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00023.html security.netapp.com: https://security.netapp.com/advisory/ntap-20231016-0001/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00024.html openwall.com: http://www.openwall.com/lists/oss-security/2023/10/18/4 openwall.com: http://www.openwall.com/lists/oss-security/2023/10/18/8 openwall.com: http://www.openwall.com/lists/oss-security/2023/10/19/6 lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/ZKQSIKIAT5TJ3WSLU3RDBQ35YX4GY4V3/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/JIZSEFC3YKCGABA2BZW6ZJRMDZJMB7PJ/ openwall.com: http://www.openwall.com/lists/oss-security/2023/10/20/8 lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/WLPRQ5TWUQQXYWBJM7ECYDAIL2YVKIUH/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/E72T67UPDRXHIDLO3OROR25YAMN4GGW5/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/BFQD3KUEMFBHPAPBGLWQC34L4OWL5HAZ/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/ZLU6U2R2IC2K64NDPNMV55AUAO65MAF4/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/X6QXN4ORIVF6XBW4WWFE7VNPVC74S45Y/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/LKYHSZQFDNR7RSA7LHVLLIAQMVYCUGBG/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/FNA62Q767CFAFHBCDKYNPBMZWB7TWYVU/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/LNMZJCDHGLJJLXO4OXWJMTVQRNWOC7UL/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/KSEGD2IWKNUO3DWY4KQGUQM5BISRWHQE/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/CLB4TW7KALB3EEQWNWCN7OUIWWVWWCG2/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00045.html debian.org: https://www.debian.org/security/2023/dsa-5540 lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00047.html discuss.hashicorp.com: 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 lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/VHUHTSXLXGXS7JYKBXTA3VINUPHTNGVU/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/VSRDIV77HNKUSM7SJC5BKE5JSHLHU2NK/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/3N4NJ7FR4X4FPZUGNTQAPSTVB2HB2Y4A/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/ZB43REMKRQR62NJEI7I5NQ4FSXNLBKRT/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/HT7T2R4MQKLIF4ODV4BDLPARWFPCJ5CZ/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/XFOIBB4YFICHDM7IBOP7PWXW3FX4HLL2/ lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/11/msg00001.html debian.org: https://www.debian.org/security/2023/dsa-5549 lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/2MBEPPC36UBVOZZNAXFHKLFGSLCMN5LI/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/[email protected]/message/WE2I52RHNNU42PX6NZ2RBUHSFFJ2LVZX/ debian.org: https://www.debian.org/security/2023/dsa-5558 lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/11/msg00012.html security.gentoo.org: https://security.gentoo.org/glsa/202311-09 debian.org: https://www.debian.org/security/2023/dsa-5570 security.netapp.com: https://security.netapp.com/advisory/ntap-20240426-0007/ security.netapp.com: https://security.netapp.com/advisory/ntap-20240621-0006/ security.netapp.com: https://security.netapp.com/advisory/ntap-20240621-0007/ github.com: https://github.com/grpc/grpc/releases/tag/v1.59.2 sec.cloudapps.cisco.com: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http2-reset-d8Kf32vZ cisa.gov: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-44487 lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JMEXY22BFG5Q64HQCM5CK2Q7KDKVV4TY/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZKQSIKIAT5TJ3WSLU3RDBQ35YX4GY4V3/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JIZSEFC3YKCGABA2BZW6ZJRMDZJMB7PJ/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WLPRQ5TWUQQXYWBJM7ECYDAIL2YVKIUH/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E72T67UPDRXHIDLO3OROR25YAMN4GGW5/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFQD3KUEMFBHPAPBGLWQC34L4OWL5HAZ/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZLU6U2R2IC2K64NDPNMV55AUAO65MAF4/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X6QXN4ORIVF6XBW4WWFE7VNPVC74S45Y/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LKYHSZQFDNR7RSA7LHVLLIAQMVYCUGBG/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FNA62Q767CFAFHBCDKYNPBMZWB7TWYVU/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LNMZJCDHGLJJLXO4OXWJMTVQRNWOC7UL/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KSEGD2IWKNUO3DWY4KQGUQM5BISRWHQE/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CLB4TW7KALB3EEQWNWCN7OUIWWVWWCG2/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VHUHTSXLXGXS7JYKBXTA3VINUPHTNGVU/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VSRDIV77HNKUSM7SJC5BKE5JSHLHU2NK/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3N4NJ7FR4X4FPZUGNTQAPSTVB2HB2Y4A/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZB43REMKRQR62NJEI7I5NQ4FSXNLBKRT/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HT7T2R4MQKLIF4ODV4BDLPARWFPCJ5CZ/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XFOIBB4YFICHDM7IBOP7PWXW3FX4HLL2/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2MBEPPC36UBVOZZNAXFHKLFGSLCMN5LI/ lists.fedoraproject.org: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WE2I52RHNNU42PX6NZ2RBUHSFFJ2LVZX/ vicarius.io: https://www.vicarius.io/vsociety/posts/rapid-reset-cve-2023-44487-dos-in-http2-understanding-the-root-cause openwall.com: http://www.openwall.com/lists/oss-security/2025/08/13/6