Home/CVE/HTTP/2 Rapid Reset Attack Vulnerability
CVE

CVE-2023-44487

HTTP/2 Rapid Reset Attack Vulnerability

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.

HIGH · CVSS 7.5 ⚠ CISA KEV EPSS 0.944
Act now
  • Listed on CISA KEV (known exploited in the wild)
  • SSVC exploitation status: active
  • EPSS ≥ 0.50 - high probability of exploitation in the next 30 days
  • EPSS percentile: top 0% of all CVEs by exploitation likelihood
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules1 YARA rules0

Required Remediation

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

Weakness Classification

Affected Products & Versions

53
siemens sinec insall versions

Affected Packages

16
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go github.com/nghttp2/nghttp2 HIGH fixed in 1.57.0
Go golang.org/x/net fixed in 0.17.0
Go google.golang.org/grpc fixed in 1.56.3, 1.57.1, 1.58.3
Go stdlib fixed in 1.20.10, 1.21.3
Maven com.typesafe.akka:akka-http-core MEDIUM fixed in 10.5.3
Maven com.typesafe.akka:akka-http-core_2.11 MEDIUM
Maven com.typesafe.akka:akka-http-core_2.12 MEDIUM fixed in 10.5.3
Maven com.typesafe.akka:akka-http-core_2.13 MEDIUM fixed in 10.5.3
Maven io.netty:netty-codec-http2 HIGH fixed in 4.1.100.Final
Maven org.apache.tomcat.embed:tomcat-embed-core MEDIUM fixed in 11.0.0-M12
Maven org.apache.tomcat:tomcat-coyote MEDIUM fixed in 11.0.0-M12
Maven org.eclipse.jetty.http2:http2-common MEDIUM fixed in 9.4.53
Maven org.eclipse.jetty.http2:http2-server MEDIUM fixed in 9.4.53
Maven org.eclipse.jetty.http2:jetty-http2-common MEDIUM fixed in 12.0.2
Maven org.eclipse.jetty.http2:jetty-http2-server MEDIUM fixed in 12.0.2
SwiftURL github.com/apple/swift-nio-http2 MEDIUM fixed in 1.28.0

Public Exploits & PoCs

2

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumTomcat WebServer Logs Deleted

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD10 Oct 2023 · 02:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.

Vendor Advisories

30
suse-csafopenSUSE-SU-2026:10751-1
rhsaRHSA-2026:8322Critical
suse-csafSUSE-SU-2026:1058-1
rhsaRHSA-2026:0722Important
rhsaRHSA-2025:23528Important
🔗

References & Sources

79
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
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