CVE-2023-44487
HTTP/2 Rapid Reset Attack Vulnerability
IETF HTTP/2
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 10 October 2023. US federal agencies were required to remediate it by 31 October 2023.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 100%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Frequently asked questions
Is CVE-2023-44487 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2023-44487.
What does CVE-2023-44487 affect?
CVE-2023-44487 affects IETF HTTP/2. 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.
How severe is CVE-2023-44487?
CVE-2023-44487 is rated HIGH with a CVSS base score of 7.5. EPSS puts the probability of exploitation in the next 30 days at 100%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 31 October 2023.
How should organisations respond to CVE-2023-44487?
Apply the vendor patch for IETF HTTP/2 as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.