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…

Description

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.

Timeline

Scores

EPSS (exploitation in 30 days)

18.8% · top 2.7% of all CVEs (8 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• n/a
• CWE-284 (opens in a new tab)All about CWE-284 and its CVEs

Affected products

• n/a

  • affected n/a

References (25)

• RHSA-2016:1420 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• http://httpd.apache.org/security/vulnerabilities_24.html (opens in a new tab)x_refsource_CONFIRMx_transferred
• GLSA-201610-02 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
• 20160706 CVE-2016-4979: HTTPD webserver - X509 Client certificate based authentication can be bypassed when HTTP/2 is used [vs] (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html (opens in a new tab)x_refsource_CONFIRMx_transferred
• http://www.apache.org/dist/httpd/CHANGES_2.4 (opens in a new tab)x_refsource_CONFIRMx_transferred
• 91566 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
• http://www.oracle.com/technetwork/topics/security/bulletinoct2016-3090566.html (opens in a new tab)x_refsource_CONFIRMx_transferred
• 1036225 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
• [oss-security] 20160705 CVE-2016-4979: HTTPD webserver - X509 Client certificate based authentication can be bypassed when HTTP/2 is used [vs] (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• https://github.com/apache/httpd/commit/2d0e4eff04ea963128a41faaef21f987272e05a2 (opens in a new tab)x_refsource_CONFIRMx_transferred
• http://packetstormsecurity.com/files/137771/Apache-2.4.20-X509-Authentication-Bypass.html (opens in a new tab)x_refsource_MISCx_transferred
• https://security.netapp.com/advisory/ntap-20180601-0001/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20190815 svn commit: r1048742 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1888194 [10/13] - /httpd/site/trunk/content/security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073139 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073146 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210330 svn commit: r1073149 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2016-4979](https://cveledger.app/badge/CVE-2016-4979.svg)](https://cveledger.app/cve/CVE-2016-4979)

Record last updated 6 Aug 2024, 00:46 UTC.