CVE-2023-44487
7.5
HIGH
CVSS 3.1
EPSS 100.0% · 100th pctCISA KEV · Exploited in the wild
2023-10-10•Updated 2026-07-14•KEV 2023-10-10
CISA Known Exploited Vulnerabilities
HTTP/2 Rapid Reset Attack Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.
Added to KEV
2023-10-10
Remediation due
2023-10-31
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA notes
This 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
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.
Severity
CVSS 3.1 · CISA7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSSVC · CISA-ADP
Exploitationactive
Automatableyes
Technical impactpartial
Affected Products
| Vendor | Product | Affected versions |
|---|---|---|
| - | - | n/a |
References
167 LinksVendor advisories
- DSA-5522
- DSA-5521
- FEDORA-2023-ed2642fd58
- FEDORA-2023-54fadada12
- FEDORA-2023-5ff7bf1dd8
- FEDORA-2023-17efd3f2cd
- FEDORA-2023-d5030c983c
- FEDORA-2023-0259c3f26f
- FEDORA-2023-2a9214af5f
- FEDORA-2023-e9c04d81c1
- FEDORA-2023-f66fc0f62a
- FEDORA-2023-4d2fd884ea
- FEDORA-2023-b2c50535cb
- FEDORA-2023-fe53e13b5b
- FEDORA-2023-4bf641255e
- DSA-5540
- FEDORA-2023-1caffb88af
- FEDORA-2023-3f70b8d406
- FEDORA-2023-7b52921cae
- FEDORA-2023-7934802344
- FEDORA-2023-dbe64661af
- FEDORA-2023-822aab0a5a
- DSA-5549
- FEDORA-2023-c0c6a91330
- FEDORA-2023-492b7be466
- DSA-5558
- GLSA-202311-09
- DSA-5570
- FEDORA-2023-ed2642fd58
- FEDORA-2023-54fadada12
- FEDORA-2023-5ff7bf1dd8
- FEDORA-2023-17efd3f2cd
- FEDORA-2023-d5030c983c
- FEDORA-2023-0259c3f26f
- FEDORA-2023-2a9214af5f
- FEDORA-2023-e9c04d81c1
- FEDORA-2023-f66fc0f62a
- FEDORA-2023-4d2fd884ea
- FEDORA-2023-b2c50535cb
- FEDORA-2023-fe53e13b5b
- FEDORA-2023-4bf641255e
- FEDORA-2023-1caffb88af
- FEDORA-2023-3f70b8d406
- FEDORA-2023-7b52921cae
- FEDORA-2023-7934802344
- FEDORA-2023-dbe64661af
- FEDORA-2023-822aab0a5a
- FEDORA-2023-c0c6a91330
- FEDORA-2023-492b7be466
Mailing lists
- [oss-security] 20231010 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [oss-security] 20231010 CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [debian-lts-announce] 20231013 [SECURITY] [DLA 3617-1] tomcat9 security update
- [oss-security] 20231013 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [oss-security] 20231013 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [debian-lts-announce] 20231016 [SECURITY] [DLA 3621-1] nghttp2 security update
- [debian-lts-announce] 20231016 [SECURITY] [DLA 3617-2] tomcat9 regression update
- [oss-security] 20231018 Vulnerability in Jenkins
- [oss-security] 20231018 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [oss-security] 20231019 CVE-2023-45802: Apache HTTP Server: HTTP/2 stream memory not reclaimed right away on RST
- [oss-security] 20231020 Re: CVE-2023-44487: HTTP/2 Rapid Reset attack against many implementations
- [debian-lts-announce] 20231030 [SECURITY] [DLA 3641-1] jetty9 security update
- [debian-lts-announce] 20231031 [SECURITY] [DLA 3638-1] h2o security update
- [debian-lts-announce] 20231105 [SECURITY] [DLA 3645-1] trafficserver security update
- [debian-lts-announce] 20231119 [SECURITY] [DLA 3656-1] netty security update
Other references
- https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73
- https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/
- https://aws.amazon.com/security/security-bulletins/AWS-2023-011/
- https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack
- https://www.nginx.com/blog/http-2-rapid-reset-attack-impacting-f5-nginx-products/
- https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/
- https://news.ycombinator.com/item?id=37831062
- https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/
- https://www.phoronix.com/news/HTTP2-Rapid-Reset-Attack
- https://github.com/envoyproxy/envoy/pull/30055
- https://github.com/haproxy/haproxy/issues/2312
- https://github.com/eclipse/jetty.project/issues/10679
- https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764
- https://github.com/nghttp2/nghttp2/pull/1961
- https://github.com/netty/netty/commit/58f75f665aa81a8cbcf6ffa74820042a285c5e61
- https://github.com/alibaba/tengine/issues/1872
- https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2
- https://news.ycombinator.com/item?id=37830987
- https://news.ycombinator.com/item?id=37830998
- https://github.com/caddyserver/caddy/issues/5877
- https://www.bleepingcomputer.com/news/security/new-http-2-rapid-reset-zero-day-attack-breaks-ddos-records/
- https://github.com/bcdannyboy/CVE-2023-44487
- https://github.com/grpc/grpc-go/pull/6703
- https://github.com/icing/mod_h2/blob/0a864782af0a942aa2ad4ed960a6b32cd35bcf0a/mod_http2/README.md?plain=1#L239-L244
- https://github.com/nghttp2/nghttp2/releases/tag/v1.57.0
- https://mailman.nginx.org/pipermail/nginx-devel/2023-October/S36Q5HBXR7CAIMPLLPRSSSYR4PCMWILK.html
- https://my.f5.com/manage/s/article/K000137106
- https://msrc.microsoft.com/blog/2023/10/microsoft-response-to-distributed-denial-of-service-ddos-attacks-against-http/2/
- https://bugzilla.proxmox.com/show_bug.cgi?id=4988
- https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9
- https://seanmonstar.com/post/730794151136935936/hyper-http2-rapid-reset-unaffected
- https://github.com/microsoft/CBL-Mariner/pull/6381
- https://groups.google.com/g/golang-announce/c/iNNxDTCjZvo
- https://github.com/facebook/proxygen/pull/466
- https://gist.github.com/adulau/7c2bfb8e9cdbe4b35a5e131c66a0c088
- https://github.com/micrictor/http2-rst-stream
- https://edg.io/lp/blog/resets-leaks-ddos-and-the-tale-of-a-hidden-cve
- https://openssf.org/blog/2023/10/10/http-2-rapid-reset-vulnerability-highlights-need-for-rapid-response/
- https://github.com/h2o/h2o/security/advisories/GHSA-2m7v-gc89-fjqf
- https://github.com/h2o/h2o/pull/3291
- https://github.com/nodejs/node/pull/50121
- https://github.com/dotnet/announcements/issues/277
- https://github.com/golang/go/issues/63417
- https://github.com/advisories/GHSA-vx74-f528-fxqg
- https://github.com/apache/trafficserver/pull/10564
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-44487
- https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.14
- https://lists.apache.org/thread/5py8h42mxfsn8l1wy6o41xwhsjlsd87q
- https://www.openwall.com/lists/oss-security/2023/10/10/6
- https://www.haproxy.com/blog/haproxy-is-not-affected-by-the-http-2-rapid-reset-attack-cve-2023-44487
- https://github.com/opensearch-project/data-prepper/issues/3474
- https://github.com/kubernetes/kubernetes/pull/121120
- https://github.com/oqtane/oqtane.framework/discussions/3367
- https://github.com/advisories/GHSA-xpw8-rcwv-8f8p
- https://netty.io/news/2023/10/10/4-1-100-Final.html
- https://www.cisa.gov/news-events/alerts/2023/10/10/http2-rapid-reset-vulnerability-cve-2023-44487
- https://www.theregister.com/2023/10/10/http2_rapid_reset_zeroday/
- https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack
- https://news.ycombinator.com/item?id=37837043
- https://github.com/kazu-yamamoto/http2/issues/93
- https://martinthomson.github.io/h2-stream-limits/draft-thomson-httpbis-h2-stream-limits.html
- https://github.com/kazu-yamamoto/http2/commit/f61d41a502bd0f60eb24e1ce14edc7b6df6722a1
- https://github.com/apache/httpd/blob/afcdbeebbff4b0c50ea26cdd16e178c0d1f24152/modules/http2/h2_mplx.c#L1101-L1113
- https://access.redhat.com/security/cve/cve-2023-44487
- https://github.com/ninenines/cowboy/issues/1615
- https://github.com/varnishcache/varnish-cache/issues/3996
- https://github.com/tempesta-tech/tempesta/issues/1986
- https://blog.vespa.ai/cve-2023-44487/
- https://github.com/etcd-io/etcd/issues/16740
- https://www.darkreading.com/cloud/internet-wide-zero-day-bug-fuels-largest-ever-ddos-event
- https://istio.io/latest/news/security/istio-security-2023-004/
- https://github.com/junkurihara/rust-rpxy/issues/97
- https://bugzilla.suse.com/show_bug.cgi?id=1216123
- https://bugzilla.redhat.com/show_bug.cgi?id=2242803
- https://ubuntu.com/security/CVE-2023-44487
- https://community.traefik.io/t/is-traefik-vulnerable-to-cve-2023-44487/20125
- https://github.com/advisories/GHSA-qppj-fm5r-hxr3
- https://github.com/apache/httpd-site/pull/10
- https://github.com/projectcontour/contour/pull/5826
- https://github.com/linkerd/website/pull/1695/commits/4b9c6836471bc8270ab48aae6fd2181bc73fd632
- https://github.com/line/armeria/pull/5232
- https://blog.litespeedtech.com/2023/10/11/rapid-reset-http-2-vulnerablilty/
- https://security.paloaltonetworks.com/CVE-2023-44487
- https://github.com/akka/akka-http/issues/4323
- https://github.com/openresty/openresty/issues/930
- https://github.com/apache/apisix/issues/10320
- https://github.com/Azure/AKS/issues/3947
- https://github.com/Kong/kong/discussions/11741
- https://github.com/arkrwn/PoC/tree/main/CVE-2023-44487
- https://www.netlify.com/blog/netlify-successfully-mitigates-cve-2023-44487/
- https://github.com/caddyserver/caddy/releases/tag/v2.7.5
- https://arstechnica.com/security/2023/10/how-ddosers-used-the-http-2-protocol-to-deliver-attacks-of-unprecedented-size/
- https://lists.w3.org/Archives/Public/ietf-http-wg/2023OctDec/0025.html
- https://linkerd.io/2023/10/12/linkerd-cve-2023-44487/
- https://security.netapp.com/advisory/ntap-20231016-0001/
- 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://security.netapp.com/advisory/ntap-20240426-0007/
- https://security.netapp.com/advisory/ntap-20240621-0006/
- https://security.netapp.com/advisory/ntap-20240621-0007/
- https://github.com/grpc/grpc/releases/tag/v1.59.2
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http2-reset-d8Kf32vZ
- https://www.vicarius.io/vsociety/posts/rapid-reset-cve-2023-44487-dos-in-http2-understanding-the-root-cause
- http://www.openwall.com/lists/oss-security/2025/08/13/6
Record Details
Published
2023-10-10
Last updated
2026-07-14
Assigner (CNA)
mitre
Credited to
-
CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.