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Vulnerability details: VCID-7zer-dq7c-8ffq
Vulnerability ID VCID-7zer-dq7c-8ffq
Aliases CVE-2016-4979
Summary For configurations enabling support for HTTP/2, SSL client certificate validation was not enforced if configured, allowing clients unauthorized access to protected resources over HTTP/2. This issue affected releases 2.4.18 and 2.4.20 only.
Status Published
Exploitability 0.5
Weighted Severity 8.2
Risk 4.1
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-287 Improper Authentication
CWE-284 Improper Access Control
System Score Found at
cvssv3 9.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2016-4979.json
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
epss 0.1736 https://api.first.org/data/v1/epss?cve=CVE-2016-4979
cvssv2 7.8 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
apache_httpd important https://httpd.apache.org/security/json/CVE-2016-4979.json
cvssv2 5.0 https://nvd.nist.gov/vuln/detail/CVE-2016-4979
cvssv3 7.5 https://nvd.nist.gov/vuln/detail/CVE-2016-4979
Reference id Reference type URL
http://httpd.apache.org/security/vulnerabilities_24.html
http://packetstormsecurity.com/files/137771/Apache-2.4.20-X509-Authentication-Bypass.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2016-4979.json
https://api.first.org/data/v1/epss?cve=CVE-2016-4979
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-4979
http://seclists.org/fulldisclosure/2016/Jul/11
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/apache/httpd/commit/2d0e4eff04ea963128a41faaef21f987272e05a2
https://lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd65286ba%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/84a3714f0878781f6ed84473d1a503d2cc382277e100450209231830%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r04e89e873d54116a0635ef2f7061c15acc5ed27ef7500997beb65d6f%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rb14daf9cc4e28d18cdc15d6a6ca74e565672fabf7ad89541071d008b%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rcc44594d4d6579b90deccd4536b5d31f099ef563df39b094be286b9e%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rd18c3c43602e66f9cdcf09f1de233804975b9572b0456cc582390b6f%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/re1e3a24664d35bcd0a0e793e0b5fc6ca6c107f99a1b2c545c5d4b467%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/re3d27b6250aa8548b8845d314bb8a350b3df326cacbbfdfe4d455234%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
https://security.netapp.com/advisory/ntap-20180601-0001/
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://www.securitytracker.com/id/1036225
1352476 https://bugzilla.redhat.com/show_bug.cgi?id=1352476
cpe:2.3:a:apache:http_server:2.4.18:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:apache:http_server:2.4.18:*:*:*:*:*:*:*
cpe:2.3:a:apache:http_server:2.4.19:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:apache:http_server:2.4.19:*:*:*:*:*:*:*
cpe:2.3:a:apache:http_server:2.4.20:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:apache:http_server:2.4.20:*:*:*:*:*:*:*
CVE-2016-4979 https://httpd.apache.org/security/json/CVE-2016-4979.json
CVE-2016-4979 https://nvd.nist.gov/vuln/detail/CVE-2016-4979
GLSA-201610-02 https://security.gentoo.org/glsa/201610-02
RHSA-2016:1420 https://access.redhat.com/errata/RHSA-2016:1420
No exploits are available.
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2016-4979.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:L/Au:N/C:C/I:N/A:N Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2016-4979
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2016-4979
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.95022
EPSS Score 0.1736
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:36:20.324032+00:00 Apache HTTPD Importer Import https://httpd.apache.org/security/json/CVE-2016-4979.json 38.0.0