CVE Intelligence
High Access control

CVE-2016-5388 — Improper Access Control in Apache Tomcat

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 Jul 18, 2016 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: redhat

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 50.9% (30-day exploitation probability)+15
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
50.9%
ahead of 99% of scored CVEs · Oct 15, 2026
Affects
Apache Software Foundation
Tomcat and 11 more
CVSS base
8.1
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Maven Org.apache.tomcat:tomcat-catalina: fixed in version 7.0.72 — github.com (GitHub Security Advisories)
  • Maven Org.apache.tomcat:tomcat-catalina: fixed in version 8.5.5 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Tomcat, Hp System Management Homepage, Oracle Linux…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apache Software Foundation Tomcat ≥ 8.0 and ≤ 8.5.4≥ 7.0 and ≤ 7.0.70≥ 6.0 and ≤ 6.0.45 Vulnerable NIST National Vulnerability Database
Hp System Management Homepage ≤ 7.5.5.0 Vulnerable NIST National Vulnerability Database
Oracle Linux version 6version 7 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Desktop version 6.0version 7.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Hpc Node version 7.0version 6.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Hpc Node Eus version 7.2 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server version 6.0version 7.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Aus version 7.2 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Eus version 7.2 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Tus version 7.2 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Workstation version 6.0version 7.0 Vulnerable NIST National Vulnerability Database
Maven Org.apache.tomcat:tomcat-catalina ≥ 7.0.0 and < 7.0.72≥ 8.0.0 and < 8.5.5 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.1 CVSS 3.0 High 2.2 5.9 nvd@nist.gov via NIST National Vulnerability Database
8.1 CVSS 3.0 High — — GitHub, Inc. via GitHub Security Advisories
5.1 CVSS 2.0 Medium 4.9 6.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-284 · Improper Access Control

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Audit administrative actions and access to resources outside each user’s normal pattern.
web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 15, 2026 · GitHub Security Advisories
  • Affected products added · maven/org.apache.tomcat:tomcat-catalina
    Oct 15, 2026 · GitHub Security Advisories
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • Fix documented
    Oct 15, 2026 · NIST National Vulnerability Database
  • Affected products added · redhat/enterprise linux desktop, redhat/enterprise linux hpc node, redhat/enterprise linux hpc node eus, redhat/enterpri
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVSS changed · 8.1
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · Alertas do Telegram
  • 2016
  • CVE published
    Jul 18, 2016 · redhat

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 15, 2026 – Oct 15, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

46 on the record

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor
Access control
same class
CWE-284
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-55957 Apache Tomcat: Authentication bypass with JNDIRealm and GSSAPI authenticated bind Jun 29, 2026
  • CVE-2026-55956 Apache Tomcat: Security constraints for default servlet ignored method Jun 29, 2026
  • CVE-2026-55955 Apache Tomcat: EncryptInterceptor not protected against replay attacks Jun 29, 2026
  • CVE-2026-55276 Apache Tomcat: Logged effective web.xml is incomplete Jun 29, 2026
  • CVE-2026-53434 Apache Tomcat CRL Configuration Flaw in FFM Connector (CWE-390) Jun 29, 2026
  • CVE-2026-53404 Apache Tomcat: Bad ornext processing in RewriteValve Jun 29, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2016-5388 is "Improper Access Control in Apache Tomcat", rated High. It affects Tomcat (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. EPSS 50.90% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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