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

criticalknown exploitedpublic exploitCVE-2023-44487

Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.

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

CSIRTS triage

vendor: HTTP/2 product: HTTP/2 Denial of service

What: HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).
Who is affected: Deployments using HTTP/2.
Urgency: Remediation is urgent due to active exploitation and critical severity.
Action: Implement rate limiting and apply updates as they become available.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CISA Known Exploited Vulnerabilities (US · database · site)
Severity: critical
Published: 2023-10-10
Exploitation: Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2023-44487

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Exploitation confirmedCVE-2023-44487Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99.9% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2023-44487	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownexploitedMultiple vulnerabilities in IBM products (August 21, 2026)cert-fr-avis
highexploited[UPDATE] [high] http/2 implementations: Vulnerability allows denial of servicecert-bund
unknownexploitedMultiple vulnerabilities in IBM products (August 14, 2026)cert-fr-avis
high[UPDATE] [high] Eclipse Jetty: Multiple vulnerabilities allow Denial of Servicecert-bund
criticalexploitedGitLab Security Release: 16.5.1, 16.4.2, 16.3.6gitlab
criticalexploitedGitLab Security Release: 16.5.1, 16.4.2, 16.3.6gitlab
unknownexploitedJenkins Security Advisory 2023-10-18jenkins

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

CSIRTS triage

Details

Exploitation outlook

Referenced CVEs

Same CVEs, other sources

More from CISA Known Exploited Vulnerabilities