CVE-2023-44487 KEVPublic exploit High · 7.5 EPSS >99.9%
HTTP/2 Rapid Reset Attack Vulnerability
IETF · HTTP/2
Summary
The HTTP/2 protocol, as specified by the IETF, contains a flaw in its request cancellation handling that lets clients reset streams in rapid succession, causing uncontrolled resource consumption on the server. An attacker with network access to an HTTP/2 endpoint can exploit this without authentication or user interaction to exhaust server resources and cause denial of service.
Official description · NVD
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.
Priority scorePatchfirst’s 0 to 100 ranking. It adds points for CISA KEV listing, ransomware use, EPSS, threat reports, public exploit code and CVSS. Every CVE page shows the breakdown. Breakdown
68.2 / 100
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 2/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited the day it was disclosed. Public exploit code (PoC-in-GitHub) was available the same day.
- DisclosedFirst seen exploitedVulnCheck KEV evidenceAdded to CISA KEVEU database agreesPublic exploit codePoC-in-GitHubday 0
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
Patch historyEarlier and later CVEs in the same code, in date order. It shows when a fix was bypassed or incomplete and which version finally fixed it.
See the family treeA fix was bypassed or incomplete 3 times over 14 months. The latest fix listed for akka-http-core_2.12 is 10.5.3.
Same bug familyLinked by evidence that a fix failed or the same code was patched again. Oldest first.
- This CVECVE-2023-44487HTTP/2 Rapid Reset Attack10 Oct 2023KEV
relatedHigh
Why these are linked: Link confidenceHow strong the evidence is that two CVEs are related. High: stated in the CVE text or linked in an advisory, or the same code was patched one release apart. Medium: the same code, or a version step plus a similar description. Low: similar description only.
- Linked in OSV/GitHub advisoryGO-2023-2102
incomplete fixHigh
Why these are linked: Link confidenceHow strong the evidence is that two CVEs are related. High: stated in the CVE text or linked in an advisory, or the same code was patched one release apart. Medium: the same code, or a version step plus a similar description. Low: similar description only.
- Stated in the CVE text
An incomplete fix was shipped for the Rapid Reset (CVE-2023-44487/CVE-2023-39325) vulnerability for an OpenShift Containers.
- Stated in the CVE text
- same family
- same family
Fixes in akka-http-core_2.12Maven package, by fixed version. Earlier and later fixes in the same package, not necessarily the same bug.
- 10.0.6CVE-2017-10001184 Oct 2017
- 10.1.4CVE-2018-1613130 Aug 2018
- 10.2.7CVE-2021-426972 Nov 2021
- 10.5.3CVE-2023-4448710 Oct 2023KEVLatest listed
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
2 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 2Initial AccessTA0001
Exploit Public-Facing Application T1190 Medium Confidence (technique links)How sure Patchfirst is that an ATT&CK technique applies to this CVE. High and medium links are shown by default; low ones come from early or generic mappings, text matching, or contradict the CVE’s details.
MITRE CTID mapping of the KEV entry · how it is exploited
This vulnerability is exploited through a 'Rapid Reset' flaw in HTTP/2 endpoints. Attackers initiate this vulnerability by sending a crafted sequence of HTTP requests using HEADERS followed by RST_STREAM frames. This allows them to generate substantial traffic on targeted servers, significantly increasing CPU usage and leading to resource exhaustion without authentication.
ImpactTA0040
Endpoint Denial of Service T1499 Medium Confidence (technique links)How sure Patchfirst is that an ATT&CK technique applies to this CVE. High and medium links are shown by default; low ones come from early or generic mappings, text matching, or contradict the CVE’s details.
MITRE CTID mapping of the KEV entry · primary impact
Detection
0 rules for this CVE · 152 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2023-44487 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploit Public-Facing ApplicationT1190149 general rules
- Arcadyan Router Exploitationscriticaltest
- Citrix ADS Exploitation CVE-2020-8193 CVE-2020-8195criticaltest
- Citrix Netscaler Attack CVE-2019-19781criticaltest
- Confluence Exploitation CVE-2019-3398criticaltest
- CVE-2010-5278 Exploitation Attemptcriticaltest
- CVE-2020-0688 Exchange Exploitation via Web Logcriticaltest
- CVE-2020-10148 SolarWinds Orion API Auth Bypasscriticaltest
- CVE-2020-5902 F5 BIG-IP Exploitation Attemptcriticaltest
Endpoint Denial of ServiceT14993 general rules
- CVE-2024-49113 Exploitation Attempt - LDAP Nightmarehighexperimental
- LSASS Crash Via Netlogon Stack Buffer Overflow - CVE-2026-41089highexperimental
- Potential Abuse of Linux Magic System Request Keymediumexperimental
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
Am I affected? What do I upgrade to?
From GitHub Security Advisories and OSV12 packages in 3 ecosystems. No single main package: each of these ships the affected code.
- SwiftURLgithub.com/apple/swift-nio-http2Affected: All versions before 1.28.0Upgrade to 1.28.0 or later
- Mavenorg.eclipse.jetty.http2:http2-commonAffected: 11.0.0 up to 11.0.17; 10.0.0 up to 10.0.17; 9.3.0 up to 9.4.53Upgrade to 11.0.17 or later (older lines: 10.0.17, 9.4.53)
- Mavenorg.eclipse.jetty.http2:http2-serverAffected: 11.0.0 up to 11.0.17; 10.0.0 up to 10.0.17; 9.3.0 up to 9.4.53Upgrade to 11.0.17 or later (older lines: 10.0.17, 9.4.53)
- Mavenorg.eclipse.jetty.http2:jetty-http2-commonAffected: 12.0.0 up to 12.0.2Upgrade to 12.0.2 or later
- Mavenorg.eclipse.jetty.http2:jetty-http2-serverAffected: 12.0.0 up to 12.0.2Upgrade to 12.0.2 or later
- Mavencom.typesafe.akka:akka-http-coreAffected: All versions before 10.5.3Upgrade to 10.5.3 or later
- Mavencom.typesafe.akka:akka-http-core_2.13Affected: All versions before 10.5.3Upgrade to 10.5.3 or later
- Mavencom.typesafe.akka:akka-http-core_2.12Affected: All versions before 10.5.3Upgrade to 10.5.3 or later
- Mavencom.typesafe.akka:akka-http-core_2.11Affected: 10.1.15 and earlierNo fixed version published
- Gogolang.org/x/netAffected: All versions before 0.17.0Upgrade to 0.60.0 or later
- Mavenorg.apache.tomcat:tomcat-coyoteAffected: 11.0.0-M1 up to 11.0.0-M12; 10.0.0 up to 10.1.14; 9.0.0 up to 9.0.81; 8.5.0 up to 8.5.94Upgrade to 10.1.40 (older lines: 11.0.6, 9.0.104, 8.5.94)
- Mavenorg.apache.tomcat.embed:tomcat-embed-coreAffected: 11.0.0-M1 up to 11.0.0-M12; 10.0.0 up to 10.1.14; 9.0.0 up to 9.0.81; 8.5.0 up to 8.5.94Upgrade to 10.1.45 (older lines: 11.0.11, 9.0.109, 8.5.94)
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 30, 202629 Oct 2026
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- 44 more on OTX