Back
CVE-2016-4979
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…
High7.5EPSS 18.8%
- Published
- Updated
- Reserved
- Assigned by
- redhat
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 18.8% · top 2.7% of all CVEs (2 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
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)
Record last updated .