CVE-2023-44487

HIGH

7.5

CVSS Score

Published: October 10, 2023 at 12:00 AM UTC

Updated: October 14, 2026 at 11:51 PM UTC

317 products affected across 33 vendorsDebian LinuxWindows Server 2016Windows Server 2019

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Severity

HIGH7.5

Exploitation

CISA KEV

Exploit prediction

EPSS 100%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score100.0%

EPSS (Exploit Prediction Scoring System) estimates a 100.0% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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

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.

Ransomware Use

Unknown

Added to KEV

Oct 10, 2023

Remediation Due

Oct 31, 2023

1091 days overdue

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

HTTP Server · Akka

95%

v < 10.5.3

Affected range stops below 10.5.3, so it looks safe — our inference, not a vendor statement

Opensearch Data Prepper · Amazon

95%

v < 2.5.0

Affected range stops below 2.5.0, so it looks safe — our inference, not a vendor statement

Apisix · Apache

95%

v < 3.6.1

Affected range stops below 3.6.1, so it looks safe — our inference, not a vendor statement

Solr · Apachemaven

95%

v < 9.4.0

Affected range stops below 9.4.0, so it looks safe — our inference, not a vendor statement

Tomcat · Apache

95%

10.1.0 ≤ v ≤ 10.1.138.5.0 ≤ v ≤ 8.5.939.0.0 ≤ v ≤ 9.0.8011.0.0 milestone1 11.0.0 milestone10 11.0.0 milestone11 11.0.0 milestone2 11.0.0 milestone3 11.0.0 milestone4 11.0.0 milestone5 11.0.0 milestone6 11.0.0 milestone7 11.0.0 milestone8 11.0.0 milestone9

Traffic Server · Apache

95%

8.0.0 ≤ v < 8.1.99.0.0 ≤ v < 9.2.3

Affected range stops below 8.1.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.2.3, so it looks safe — our inference, not a vendor statement

Swiftnio HTTP /2 · Apple

95%

v < 1.28.0

Affected range stops below 1.28.0, so it looks safe — our inference, not a vendor statement

Caddy · Caddyserver

95%

v < 2.7.5

Affected range stops below 2.7.5, so it looks safe — our inference, not a vendor statement

Business Process Automation · Cisco

95%

v < 3.2.003.009

Affected range stops below 3.2.003.009, so it looks safe — our inference, not a vendor statement

Connected Mobile Experiences · Cisco

95%

v < 11.1

Affected range stops below 11.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references