⚠ Actively exploited
Added to CISA KEV on 2023-10-10. Federal agencies required to patch by 2023-10-31. 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..

CVE-2023-44487

Severity
7.5HIGH
EPSS
94.4%
top 0.03%
CISA KEV
KEV
Added 2023-10-10
Due 2023-10-31
Exploit
Exploited in wild
Active exploitation observed
Timeline
PublishedOct 10
KEV addedOct 10
KEV dueOct 31
Latest updateNov 26
CISA 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.

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages139 packages

NVDakka/http_server< 10.5.3
Mavenorg.eclipse.jetty.http2:http2-server9.3.09.4.53+2
NVDgolang/http2< 0.17.0

Also affects: Debian Linux 10.0, 11.0, 12.0, Fedora 37, 38, Enterprise Linux 6.0, 8.0, 9.0, Openshift Container Platform 4.0

Patches

🔴Vulnerability Details

15
OSV
netty vulnerabilities2024-09-05
OSV
nghttp2 vulnerability2024-05-07
OSV
dotnet6, dotnet7 vulnerabilities2023-10-19
GHSA
github.com/kumahq/kuma affected by CVE-2023-444872023-10-17
OSV
github.com/kumahq/kuma affected by CVE-2023-444872023-10-17

💥Exploits & PoCs

1
Exploit-DB
HTTP/2 2.0 - Denial Of Service (DOS)2025-09-16

📋Vendor Advisories

28
Ubuntu
H2O vulnerability2025-11-26
Ubuntu
H2O vulnerability2025-04-30
Ubuntu
Node.js vulnerability2025-04-29
Ubuntu
Apache Traffic Server vulnerability2025-04-28
Ubuntu
Apache Tomcat vulnerability2025-04-28

🕵️Threat Intelligence

5
Talos
What to know about the HTTP/2 Rapid Reset DDoS attacks2023-10-11
Talos
What to know about the HTTP/2 Rapid Reset DDoS attacks2023-10-11
Qualys
Understanding the HTTP/2 Rapid Reset Attack (CVE-2023-44487) | Qualys2023-10-10
Qualys
CVE-2023-44487 HTTP/2 Rapid Reset Attack2023-10-10
Huntress
CVE-2023-44487 Vulnerability: Analysis, Impact, Mitigation | Huntress