HTTP/2 Stream Cancellation Attack
The HTTP/2 protocol allows clients to indicate to the server that a previous stream should be canceled by sending a RST_STREAM frame. The protocol does not require the client and server to coordinate the cancellation in any way, the client may do it unilaterally. The client may also assume that the cancellation will take effect immediately when the server receives the RST_STREAM frame, before any other data from that TCP connection is processed.
Abuse of this feature is called a Rapid Reset attack because it relies on the ability for an endpoint to send a RST_STREAM frame immediately after sending a request frame, which makes the other endpoint start working and then rapidly resets the request. The request is canceled, but leaves the HTTP/2 connection open.
The HTTP/2 Rapid Reset attack built on this capability is simple: The client opens a large number of streams at once as in the standard HTTP/2 attack, but rather than waiting for a response to each request stream from the server or proxy, the client cancels each request immediately.
The ability to reset streams immediately allows each connection to have an indefinite number of requests in flight. By explicitly canceling the requests, the attacker never exceeds the limit on the number of concurrent open streams. The number of in-flight requests is no longer dependent on the round-trip time (RTT), but only on the available network bandwidth.
In a typical HTTP/2 server implementation, the server will still have to do significant amounts of work for canceled requests, such as allocating new stream data structures, parsing the query and doing header decompression, and mapping the URL to a resource. For reverse proxy implementations, the request may be proxied to the backend server before the RST_STREAM frame is processed. The client on the other hand paid almost no costs for sending the requests. This creates an exploitable cost asymmetry between the server and the client.
Multiple software artifacts implementing HTTP/2 are affected. This advisory was originally ingested from the swift-nio-http2 repo advisory and their original conent follows.
swift-nio-http2 is vulnerable to a denial-of-service vulnerability in which a malicious client can create and then reset a large number of HTTP/2 streams in a short period of time. This causes swift-nio-http2 to commit to a large amount of expensive work which it then throws away, including creating entirely new Channels to serve the traffic. This can easily overwhelm an EventLoop and prevent it from making forward progress.
swift-nio-http2 1.28 contains a remediation for this issue that applies reset counter using a sliding window. This constrains the number of stream resets that may occur in a given window of time. Clients violating this limit will have their connections torn down. This allows clients to continue to cancel streams for legitimate reasons, while constraining malicious actors.
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVE-2023-44487 is classified as CWE-400: Uncontrolled Resource Consumption. A request can consume memory, CPU or storage without limit, exhausting capacity for everyone else.
CVE-2023-44487 is recorded against 194 packages.
Published on 10 October 2023 and last revised on 11 August 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.
www.openwall.com
www.openwall.com
www.openwall.com
www.openwall.com
www.openwall.com
www.openwall.com
www.openwall.com
www.openwall.com
access.redhat.com
arstechnica.com
aws.amazon.com
blog.cloudflare.com
blog.cloudflare.com
blog.litespeedtech.com
blog.qualys.com
blog.vespa.ai
bugzilla.proxmox.com
bugzilla.redhat.com
bugzilla.suse.com
cgit.freebsd.org
cloud.google.com
cloud.google.com
community.traefik.io
discuss.hashicorp.com
edg.io
forums.swift.org
gist.github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
github.com
.net has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-400: Uncontrolled Resource Consumption) in other software:
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| .net | 7.0.0 | 7.0.12 |
| 3scale-api-management-platform | — | — |
| advanced-cluster-management-for-kubernetes | — | — |
| advanced-cluster-security | — | — |
| ansible-automation-platform | — | — |
| apisix | — | — |
| armeria | — | 1.26.0 |
| asp.net-core | 7.0.0 | 7.0.12 |
| aspnet-core | — | — |
| astra-control-center | — | — |
| azure-kubernetes-service | — | 2023-10-08 |
| big-ip-access-policy-manager | — | — |
| big-ip-advanced-firewall-manager | — | — |
| big-ip-advanced-web-application-firewall | — | — |
| big-ip-analytics | — | — |
| big-ip-application-acceleration-manager | — | — |
| big-ip-application-security-manager | — | — |
| big-ip-application-visibility-and-reporting | — | — |
| big-ip-carrier-grade-nat | — | — |
| big-ip-ddos-hybrid-defender | — | — |
| big-ip-domain-name-system | — | — |
| big-ip-fraud-protection-service | — | — |
| big-ip-global-traffic-manager | — | — |
| big-ip-link-controller | — | — |
| big-ip-local-traffic-manager | — | — |
| big-ip-next | — | — |
| big-ip-next-service-proxy-for-kubernetes | 1.5.0 | 1.8.2 |
| big-ip-policy-enforcement-manager | — | — |
| big-ip-ssl-orchestrator | — | — |
| big-ip-webaccelerator | — | — |
| big-ip-websafe | — | — |
| build-of-optaplanner | — | — |
| build-of-quarkus | — | — |
| business-process-automation | — | 3.2.003.009 |
| caddy | — | 2.7.5 |
| cbl-mariner | — | 2023-10-11 |
| ceph-storage | — | — |
| cert-manager-operator-for-red-hat-openshift | — | — |
| certification-for-red-hat-enterprise-linux | — | — |
| cluster-autoscaler-1.26 | — | 1.26.4-r4 |
| cluster-autoscaler-1.26-compat | — | 1.26.4-r4 |
| cluster-autoscaler-1.27 | — | 1.27.3-r6 |
| cluster-autoscaler-1.27-compat | — | 1.27.3-r6 |
| cluster-autoscaler-1.28 | — | 1.28.0-r6 |
| cluster-autoscaler-1.28-compat | — | 1.28.0-r6 |
| com.typesafe.akka:akka-http-core | — | 10.5.3 |
| com.typesafe.akka:akka-http-core-2.11 | — | — |
| com.typesafe.akka:akka-http-core-2.12 | — | 10.5.3 |
| com.typesafe.akka:akka-http-core-2.13 | — | 10.5.3 |
| connected-mobile-experiences | — | 11.1 |
| contour | — | — |
| cost-management | — | — |
| crosswork-data-gateway | 5.0.0 | 5.0.2 |
| crosswork-situation-manager | — | — |
| crosswork-zero-touch-provisioning | — | 6.0.0 |
| cryostat | — | — |
| data-center-network-manager | — | — |
| debian-linux | — | — |
| decision-manager | — | — |
| dotnet | — | — |
| dotnet-sdk | — | — |
| enterprise-chat-and-email | — | — |
| enterprise-linux | — | — |
| envoy | — | — |
| expressway | — | x14.3.3 |
| fedora | — | — |
| fence-agents-remediation-operator | — | — |
| fog-director | — | 1.22 |
| github.com/apple/swift-nio-http2 | — | — |
| go | 1.21.0 | 1.21.3 |
| golang | — | — |
| golang.org/x/net | — | — |
| grpc | — | — |
| h2o | — | 2023-10-10 |
| http | — | — |
| http-server | — | 10.5.3 |
| http2 | — | 4.2.2 |
| integration-camel-for-spring-boot | — | — |
| integration-camel-k | — | — |
| integration-service-registry | — | — |
| ios-xe | — | 17.15.1 |
| ios-xr | — | 7.11.2 |
| iot-field-network-director | — | 4.11.0 |
| istio | 1.19.0 | 1.19.1 |
| jboss-a-mq | — | — |
| jboss-a-mq-streams | — | — |
| jboss-core-services | — | — |
| jboss-data-grid | — | — |
| jboss-enterprise-application-platform | — | — |
| jboss-fuse | — | — |
| jenkins | — | — |
| jetty | 12.0.0 | 12.0.2 |
| k3d | — | 5.6.0-r6 |
| keda-2.8 | — | 2.8.2-r3 |
| keda-2.9 | — | 2.9.1-r5 |
| kong | — | — |
| kong-gateway | — | 3.4.2 |
| linkerd | — | — |
| logging-subsystem-for-red-hat-openshift | — | — |
| machine-deletion-remediation-operator | — | — |
| migration-toolkit-for-applications | — | — |
| migration-toolkit-for-containers | — | — |
| migration-toolkit-for-virtualization | — | — |
| netty | — | 4.1.100 |
| network-observability-operator | — | — |
| networking | — | 0.17.0 |
| nghttp2 | — | 1.57.0 |
| nginx | — | — |
| nginx-gateway | — | — |
| nginx-ingress-controller | — | — |
| nginx-plus | — | — |
| node | — | — |
| node-healthcheck-operator | — | — |
| node-maintenance-operator | — | — |
| node-min | — | — |
| node.js | 20.0.0 | 20.8.1 |
| nx-os | 10.4\(1\) | 10.4\(2\) |
| oncommand-insight | — | — |
| openresty | — | 1.21.4.3 |
| opensearch-data-prepper | — | 2.5.0 |
| openshift | — | — |
| openshift-api-for-data-protection | — | — |
| openshift-container-platform | — | — |
| openshift-container-platform-assisted-installer | — | — |
| openshift-data-science | — | — |
| openshift-dev-spaces | — | — |
| openshift-developer-tools-and-services | — | — |
| openshift-distributed-tracing | — | — |
| openshift-gitops | — | — |
| openshift-pipelines | — | — |
| openshift-sandboxed-containers | — | — |
| openshift-secondary-scheduler-operator | — | — |
| openshift-serverless | — | — |
| openshift-service-mesh | — | — |
| openshift-virtualization | — | — |
| openstack-platform | — | — |
| org.apache.tomcat:tomcat-coyote | 8.5.0 | 8.5.94 |
| org.apache.tomcat.embed:tomcat-embed-core | 8.5.0 | 8.5.94 |
| org.eclipse.jetty.http2:http2-common | 11.0.0 | 11.0.17 |
| org.eclipse.jetty.http2:http2-server | 11.0.0 | 11.0.17 |
| org.eclipse.jetty.http2:jetty-http2-common | 12.0.0 | 12.0.2 |
| org.eclipse.jetty.http2:jetty-http2-server | 12.0.0 | 12.0.2 |
| prime-access-registrar | — | 9.3.3 |
| prime-cable-provisioning | — | 7.2.1 |
| prime-infrastructure | — | 3.10.4 |
| prime-network-registrar | — | 11.2 |
| process-automation | — | — |
| proxygen | — | 2023.10.16.00 |
| quay | — | — |
| ruggedcom-ape1808-firmware | — | — |
| run-once-duration-override-operator | — | — |
| satellite | — | — |
| secure-dynamic-attributes-connector | — | 2.2.0 |
| secure-firewall-threat-defense | — | 7.4.2 |
| secure-malware-analytics | — | 2.19.2 |
| secure-web-appliance-firmware | — | 15.1.0 |
| self-node-remediation-operator | — | — |
| service-interconnect | — | — |
| service-telemetry-framework | — | — |
| simatic-s7-1500-cpu-1518-4-pn\/dp-mfp-firmware | 3.1.5 | — |
| simatic-s7-1500-cpu-1518f-4-pn\/dp-mfp-firmware | 3.1.5 | — |
| sinec-ins | — | — |
| sinec-nms | — | 3.0 |
| single-sign-on | — | — |
| siplus-s7-1500-cpu-1518-4-pn\/dp-mfp-firmware | 3.1.5 | — |
| solr | — | — |
| st7-scadaconnect | — | 1.1 |
| support-for-spring-boot | — | — |
| swiftnio-http\/2 | — | 1.28.0 |
| telepresence-video-communication-server | — | x14.3.3 |
| tomcat | — | — |
| traefik | — | — |
| traffic-server | 9.0.0 | 9.2.3 |
| ultra-cloud-core---policy-control-function | — | — |
| ultra-cloud-core---serving-gateway-function | — | 2024.02.0 |
| ultra-cloud-core---session-management-function | — | 2024.02.0 |
| unified-attendant-console-advanced | — | — |
| unified-contact-center-domain-manager | — | — |
| unified-contact-center-enterprise | — | — |
| unified-contact-center-enterprise---live-data-server | — | 12.6.2 |
| unified-contact-center-management-portal | — | — |
| varnish | — | — |
| varnish-cache | — | 2023-10-10 |
| visual-studio-2022 | 17.7 | 17.7.5 |
| web-terminal | — | — |
| windows-10-1607 | — | 10.0.14393.6351 |
| windows-10-1809 | — | 10.0.17763.4974 |
| windows-10-21h2 | — | 10.0.19044.3570 |
| windows-10-22h2 | — | 10.0.19045.3570 |
| windows-11-21h2 | — | 10.0.22000.2538 |
| windows-11-22h2 | — | 10.0.22621.2428 |
| windows-server-2016 | — | — |
| windows-server-2019 | — | — |
| windows-server-2022 | — | — |
References
Similar Threats
Exploit Protection
CVE-2023-44487 carries CVSS 8.0 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
Check My Site For CVE-2023-44487 →No credit card required · Results in minutes
ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
Stay up to date with the latest from Boteraser.
We use cookies to improve your experience on our site. By using our site, you consent to cookies.
Manage your cookie preferences below:
Essential cookies enable basic functions and are necessary for the proper function of the website.
CloudFlare provides web performance and security solutions, enhancing site speed and protecting against threats.
Service URL: developers.cloudflare.com (opens in a new window)
These cookies are needed for adding comments on this website.
These cookies are used for managing login functionality on this website.
Statistics cookies collect information anonymously. This information helps us understand how visitors use our website.
Google Analytics is a powerful tool that tracks and analyzes website traffic for informed marketing decisions.
Service URL: policies.google.com (opens in a new window)
You can find more information in our Cookie Policy and Privacy Policy.