CVE-2016-4979

7.5 highEPSS 19%

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.

Severity

CVSS 3.0

7.5 high

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS: 19% chance of exploitation in the next 30 days; higher than 97% of CVEs (scores of 2026-10-31)
CWE: CWE-284
Published: 2016-07-06
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

apache:http_server

References

http://httpd.apache.org/security/vulnerabilities_24.html
http://packetstormsecurity.com/files/137771/Apache-2.4.20-X509-Authentication-Bypass.html
http://seclists.org/fulldisclosure/2016/Jul/11
http://www.apache.org/dist/httpd/CHANGES_2.4
http://www.openwall.com/lists/oss-security/2016/07/05/5

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