CVE-2016-5388

Apache Tomcat 7.x through 7.0.70 and 8.x through 8.5.4, when the CGI Servlet is enabled, follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted 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. NOTE: the vendor states "A mitigation is planned for future releases of Tomcat, tracked as CVE-2016-5388"; in other words, this is not a CVE ID for a vulnerability.

Published: 2016-07-19 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2016-5388 is rated High Risk (71.4/100): CVSS High severity, with high exploitation likelihood (EPSS 36.76%, 97th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +5.54% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize 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-2016-5388

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 2026-04-04 31.22% 36.76% +5.54%
2 2026-03-30 36.76% 31.22% -5.54%
3 2026-03-04 36.76%

Full EPSS history (47 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-5388

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.0 HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
2.2 5.9 [email protected]
5.1 2.0 MEDIUM
AV:N/AC:H/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:H)
Exploitation requires uncommon or highly specific conditions.
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.
4.9 6.4 [email protected]

Weakness enumeration for CVE-2016-5388

GitHub Security Advisory for CVE-2016-5388

GHSA-v646-rx6w-r3qq · Severity: high · Ecosystem: maven — Improper Access Control in Apache Tomcat

OS Trackers for CVE-2016-5388

vendor priority summary link
debian unimportant CVE-2016-5388 unimportant priority: Debian including 1 source packages (tomcat9), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-5388
redhat medium https://access.redhat.com/security/cve/CVE-2016-5388
suse medium CVE-2016-5388 severity moderate: SUSE including 36 source package names (tomcat-7.0.54-8.el7_2, tomcat-7.0.78-7.13.4, …), 94 product×package rows across 11 product lines (SUSE Liberty Linux 7, SUSE Linux Enterprise Point of Sale 11 SP3, … (11 product lines)): Fixed 94. https://www.suse.com/security/cve/CVE-2016-5388/
ubuntu low CVE-2016-5388 low priority: Ubuntu including 3 source packages (tomcat6, tomcat7, tomcat8), 72 status rows across 24 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, precise, questing, trusty, upstream, wily, xenial, yakkety, zesty): DNE 49, ignored 8, released 6, not-affected 5, needed 3, needs-triage 1. https://ubuntu.com/security/CVE-2016-5388

Affected software / configurations for CVE-2016-5388

Vendor Product Version Raw CPE
redhat enterprise_linux_desktop 7.0 cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_hpc_node 7.0 cpe:2.3:o:redhat:enterprise_linux_hpc_node:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_hpc_node_eus 7.2 cpe:2.3:o:redhat:enterprise_linux_hpc_node_eus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server 7.0 cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 7.0 cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
hp system_management_homepage <= 7.5.5.0 cpe:2.3:a:hp:system_management_homepage:*:*:*:*:*:*:*:*
redhat enterprise_linux_desktop 6.0 cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_hpc_node 6.0 cpe:2.3:o:redhat:enterprise_linux_hpc_node:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 6.0 cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 6.0 cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
oracle linux 6 cpe:2.3:o:oracle:linux:6:*:*:*:*:*:*:*
oracle linux 7 cpe:2.3:o:oracle:linux:7:*:*:*:*:*:*:*
apache tomcat >= 6.0, <= 6.0.45 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 7.0, <= 7.0.70 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 8.0, <= 8.5.4 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*

References for CVE-2016-5388

URL Tags
http://lists.opensuse.org/opensuse-updates/2016-09/msg00025.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-1624.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-2045.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-2046.html Third Party Advisory
http://www.kb.cert.org/vuls/id/797896 Third Party Advisory US Government Resource
http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html Patch Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html Third Party Advisory
http://www.securityfocus.com/bid/91818 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1036331 Third Party Advisory VDB Entry Vendor Advisory
https://access.redhat.com/errata/RHSA-2016:1635 Third Party Advisory
https://access.redhat.com/errata/RHSA-2016:1636 Third Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03770en_us Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05320149 Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05324759 Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05390722 Third Party Advisory
https://httpoxy.org/ Third Party Advisory
https://lists.apache.org/thread.html/053d9ce4d579b02203db18545fee5e33f35f2932885459b74d1e4272%40%3Cissues.activemq.apache.org%3E
https://lists.apache.org/thread.html/6b414817c2b0bf351138911c8c922ec5dd577ebc0b9a7f42d705752d%40%3Cissues.activemq.apache.org%3E
https://lists.apache.org/thread.html/6d3d34adcf3dfc48e36342aa1f18ce3c20bb8e4c458a97508d5bfed1%40%3Cissues.activemq.apache.org%3E
https://lists.apache.org/thread.html/r2853582063cfd9e7fbae1e029ae004e6a83482ae9b70a698996353dd%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rc6b2147532416cc736e68a32678d3947b7053c3085cf43a9874fd102%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rf21b368769ae70de4dee840a3228721ae442f1d51ad8742003aefe39%40%3Cusers.tomcat.apache.org%3E
https://lists.debian.org/debian-lts-announce/2019/08/msg00015.html
https://tomcat.apache.org/tomcat-7.0-doc/changelog.html Release Notes Vendor Advisory
https://www.apache.org/security/asf-httpoxy-response.txt Vendor Advisory
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