The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not properly recognize the "SSLVerifyClient require" directive for HTTP/2 request authorization, which allows remote attackers to bypass intended access restrictions by leveraging the ability to send multiple requests over a single connection and aborting a renegotiation.
http://httpd.apache.org/security/vulnerabilities_24.html
https://github.com/apache/httpd/commit/2d0e4eff04ea963128a41faaef21f987272e05a2
http://www.apache.org/dist/httpd/CHANGES_2.4
http://www.openwall.com/lists/oss-security/2016/07/05/5
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html
http://www.oracle.com/technetwork/topics/security/bulletinoct2016-3090566.html
http://www.securityfocus.com/bid/91566
http://seclists.org/fulldisclosure/2016/Jul/11
http://packetstormsecurity.com/files/137771/Apache-2.4.20-X509-Authentication-Bypass.html
https://access.redhat.com/errata/RHSA-2016:1420
http://www.securitytracker.com/id/1036225
https://security.gentoo.org/glsa/201610-02
https://security.netapp.com/advisory/ntap-20180601-0001/
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
https://lists.apache.org/thread.html/[email protected]%3Ccvs.httpd.apache.org%3E
Source: MITRE
Published: 2016-07-06
Updated: 2021-06-06
Type: CWE-284
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH