CVE-2016-4694

The Apache HTTP Server in Apple OS X before 10.12 and OS X Server before 5.2 follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted CGI client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect an application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue, a related issue to CVE-2016-5387.

Published: 2016-09-25 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-4694 is rated Moderate Risk (60.5/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.34%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-4694

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.96% 1.34% +0.38%
2 2025-07-16 1.12% 0.96% -0.15%
3 2025-03-30 — 1.12% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-4694

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2016-4694

OS Trackers for CVE-2016-4694

vendor priority summary link
ubuntu medium CVE-2016-4694 medium priority: Ubuntu including 1 source packages (apache2), 4 status rows across 4 suites (precise, trusty, upstream, xenial): not-affected 4. https://ubuntu.com/security/CVE-2016-4694

Affected software / configurations for CVE-2016-4694

Vendor Product Version Raw CPE
apple mac_os_x <= 10.11.6 cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
apple os_x_server <= 5.1 cpe:2.3:o:apple:os_x_server:*:*:*:*:*:*:*:*

References for CVE-2016-4694

cvelogic Threat Intelligence