CVE-2023-44487: HTTP/2 Rapid Reset Attack Vulnerability

Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-d011b3564899, updated 2026-11-02T23:39:54.475Z.

CISA Known Exploited Vulnerabilities

Name
HTTP/2 Rapid Reset Attack Vulnerability
Vendor
IETF
Product
HTTP/2
Added to the catalog
2023-10-10
Due date for US federal agencies
2023-10-31
Weaknesses
CWE-400
Catalog version
2026.10.30

HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).

Required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status
Analyzed
Published
2023-10-10T14:15:10.883
Last modified
2026-08-11T19:37:30.880
Weaknesses
NVD-CWE-noinfo, CWE-400

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.

MetricScoreSeverityVectorScored by
CVSS 3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H[email protected] (Primary)
CVSS 3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

References

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:08.214Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2023-44487

CVE record

Assigner
mitre
State
PUBLISHED
Published
2023-10-10T00:00:00.000Z
Updated
2026-10-14T23:51:51.782Z
Problem types
n/a

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.

References

Read on 2026-11-03T02:04:48.008Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2023/44xxx/CVE-2023-44487.json

GitHub Advisory Database

GHSA-qppj-fm5r-hxr3: HTTP/2 Stream Cancellation Attack

Severity (GitHub)
medium
CVSS
5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:H
Weaknesses
CWE-400
Published
2023-10-10T21:28:24Z
Updated
2026-05-13T15:25:13Z
  • go golang.org/x/net: affected < 0.17.0, first patched 0.17.0
  • maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 11.0.0-M1, < 11.0.0-M12, first patched 11.0.0-M12
  • maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 10.0.0, < 10.1.14, first patched 10.1.14
  • maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 9.0.0, < 9.0.81, first patched 9.0.81
  • maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 8.5.0, < 8.5.94, first patched 8.5.94
  • swift github.com/apple/swift-nio-http2: affected < 1.28.0, first patched 1.28.0
  • maven org.eclipse.jetty.http2:http2-common: affected >= 9.3.0, < 9.4.53, first patched 9.4.53
  • maven org.eclipse.jetty.http2:http2-common: affected >= 10.0.0, < 10.0.17, first patched 10.0.17
  • maven org.eclipse.jetty.http2:http2-common: affected >= 11.0.0, < 11.0.17, first patched 11.0.17
  • maven org.eclipse.jetty.http2:http2-server: affected >= 9.3.0, < 9.4.53, first patched 9.4.53
  • maven org.eclipse.jetty.http2:http2-server: affected >= 10.0.0, < 10.0.17, first patched 10.0.17
  • maven org.eclipse.jetty.http2:http2-server: affected >= 11.0.0, < 11.0.17, first patched 11.0.17
  • maven org.eclipse.jetty.http2:jetty-http2-common: affected >= 12.0.0, < 12.0.2, first patched 12.0.2
  • maven org.eclipse.jetty.http2:jetty-http2-server: affected >= 12.0.0, < 12.0.2, first patched 12.0.2
  • maven com.typesafe.akka:akka-http-core: affected < 10.5.3, first patched 10.5.3
  • maven com.typesafe.akka:akka-http-core_2.13: affected < 10.5.3, first patched 10.5.3
  • maven com.typesafe.akka:akka-http-core_2.12: affected < 10.5.3, first patched 10.5.3
  • maven com.typesafe.akka:akka-http-core_2.11: affected <= 10.1.15
  • maven org.apache.tomcat:tomcat-coyote: affected >= 11.0.0-M1, < 11.0.0-M12, first patched 11.0.0-M12
  • maven org.apache.tomcat:tomcat-coyote: affected >= 10.0.0, < 10.1.14, first patched 10.1.14
  • maven org.apache.tomcat:tomcat-coyote: affected >= 9.0.0, < 9.0.81, first patched 9.0.81
  • maven org.apache.tomcat:tomcat-coyote: affected >= 8.5.0, < 8.5.94, first patched 8.5.94

## HTTP/2 Rapid reset 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 specific advisory
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 `Channel`s 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.

Read on 2026-11-03T08:52:24.560Z under licence ghsa-cc-by-4.0@9e5f1b3c from https://api.github.com/advisories/GHSA-qppj-fm5r-hxr3

Also known as / affected packages

GHSA-qppj-fm5r-hxr3

Also known as: CVE-2023-44487. OSV.dev record, GitHub advisory.

  • SwiftURL github.com/apple/swift-nio-http2: introduced 0, fixed 1.28.0
  • Go golang.org/x/net: introduced 0, fixed 0.17.0
  • Maven org.apache.tomcat:tomcat-coyote: introduced 11.0.0-M1, fixed 11.0.0-M12
  • Maven org.apache.tomcat:tomcat-coyote: introduced 10.0.0, fixed 10.1.14
  • Maven org.apache.tomcat:tomcat-coyote: introduced 9.0.0, fixed 9.0.81
  • Maven org.apache.tomcat:tomcat-coyote: introduced 8.5.0, fixed 8.5.94
  • Maven org.apache.tomcat.embed:tomcat-embed-core: introduced 11.0.0-M1, fixed 11.0.0-M12
  • Maven org.apache.tomcat.embed:tomcat-embed-core: introduced 10.0.0, fixed 10.1.14
  • Maven org.apache.tomcat.embed:tomcat-embed-core: introduced 9.0.0, fixed 9.0.81
  • Maven org.apache.tomcat.embed:tomcat-embed-core: introduced 8.5.0, fixed 8.5.94
  • Maven org.eclipse.jetty.http2:http2-common: introduced 9.3.0, fixed 9.4.53
  • Maven org.eclipse.jetty.http2:http2-common: introduced 10.0.0, fixed 10.0.17
  • Maven org.eclipse.jetty.http2:http2-common: introduced 11.0.0, fixed 11.0.17
  • Maven org.eclipse.jetty.http2:http2-server: introduced 9.3.0, fixed 9.4.53
  • Maven org.eclipse.jetty.http2:http2-server: introduced 10.0.0, fixed 10.0.17
  • Maven org.eclipse.jetty.http2:http2-server: introduced 11.0.0, fixed 11.0.17
  • Maven org.eclipse.jetty.http2:jetty-http2-common: introduced 12.0.0, fixed 12.0.2
  • Maven org.eclipse.jetty.http2:jetty-http2-server: introduced 12.0.0, fixed 12.0.2
  • Maven com.typesafe.akka:akka-http-core: introduced 0, fixed 10.5.3
  • Maven com.typesafe.akka:akka-http-core_2.13: introduced 0, fixed 10.5.3
  • Maven com.typesafe.akka:akka-http-core_2.12: introduced 0, fixed 10.5.3
  • Maven com.typesafe.akka:akka-http-core_2.11: introduced 0, last_affected 10.1.15

Read on 2026-11-03T01:53:38.010Z under licence ghsa-cc-by-4.0@9e5f1b3c from https://api.osv.dev/v1/vulns/GHSA-qppj-fm5r-hxr3

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

Sources and licences

  • CISA

    Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.

    CC0 1.0 Universal

  • National Vulnerability Database (NIST)

    This product uses the NVD API but is not endorsed or certified by the NVD.

    NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)

  • CVE Program, The MITRE Corporation

    Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

    CVE Program Terms of Use ("CVE Usage" licence)

  • GitHub Advisory Database

    Source: GitHub Advisory Database, https://github.com/advisories/GHSA-qppj-fm5r-hxr3, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Changes: fields selected and reformatted by ransomware-tracker.com.

    CC BY 4.0

  • GitHub Advisory Database via OSV.dev

    GHSA-qppj-fm5r-hxr3: GitHub Advisory Database, https://github.com/advisories/GHSA-qppj-fm5r-hxr3. Licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), provided as is, without warranties. Retrieved via OSV.dev (https://osv.dev/vulnerability/GHSA-qppj-fm5r-hxr3), which enriches records; fields selected and reformatted by ransomware-tracker.com.

    CC BY 4.0

  • MITRE D3FEND

    MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
    "The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

    MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT

Cite this page

Dragons Eye Ransomware Tracker, "CVE-2023-44487: HTTP/2 Rapid Reset Attack Vulnerability",
entity page, dataset version ref-d011b3564899, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2023-44487 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-08-11T19:37:30.880.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2026-10-14T23:51:51.782Z.
Underlying source: GitHub Advisory Database, GHSA-qppj-fm5r-hxr3, updated 2026-05-13T15:25:13Z.
Underlying source: GitHub Advisory Database, GHSA-qppj-fm5r-hxr3, via OSV.dev, modified 2026-09-10T03:50:04.757558216Z.
Underlying source: MITRE D3FEND, ontology version 1.6.0.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.

CISA KEV index