In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections. A possible mitigation is to not enable the h2 protocol.
https://httpd.apache.org/security/vulnerabilities_24.html
http://www.securitytracker.com/id/1041713
http://www.securityfocus.com/bid/105414
https://usn.ubuntu.com/3783-1/
https://access.redhat.com/errata/RHSA-2018:3558
https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html
https://security.netapp.com/advisory/ntap-20190204-0004/
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03909en_us
https://access.redhat.com/errata/RHSA-2019:0367
https://access.redhat.com/errata/RHSA-2019:0366
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00030.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00056.html
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://www.tenable.com/security/tns-2019-09
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
Source: MITRE
Published: 2018-09-25
Updated: 2021-06-06
Type: NVD-CWE-noinfo
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 5.9
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 2.2
Severity: MEDIUM