CVE Intelligence
Medium Open redirect

CVE-2018-11784 — Apache Tomcat Open Redirect vulnerability

When the default servlet in Apache Tomcat versions 9.0.0.M1 to 9.0.11, 8.5.0 to 8.5.33 and 7.0.23 to 7.0.90 returned a redirect to a directory (e.g. redirecting to '/foo/' when the user requested '/foo') a specially crafted URL could be used to cause the redirect to be generated to any URI of the attackers choice.

Published Oct 4, 2018 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: apache

Who exploits it and how urgent it is

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

Detection templates (Nuclei) · 1Exploit-DB · 1
How the score was calculated
  • Public exploit/PoC (nuclei, exploitdb)+12
  • EPSS 97.7% (30-day exploitation probability)+15
  • Technical severity (medium)+3

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
97.68%
ahead of 100% of scored CVEs · Oct 15, 2026
Affects
Apache Software Foundation
Tomcat and 15 more
CVSS base
4.3
Medium · 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)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Maven Org.apache.tomcat.embed:tomcat-embed-core: fixed in version 8.5.34 — github.com (GitHub Security Advisories)
  • Maven Org.apache.tomcat.embed:tomcat-embed-core: fixed in version 7.0.91 — github.com (GitHub Security Advisories)
  • Maven Org.apache.tomcat.embed:tomcat-embed-core: fixed in version 9.0.12 — 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, Canonical Ubuntu Linux, Debian Debian 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. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
  6. Search available logs for exploit probes matching the vulnerability class (open redirect), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apache Software Foundation Tomcat version 9.0.0-milestone21version 9.0.0-milestone14version 9.0.0-milestone15version 9.0.0-milestone16version 9.0.0-milestone17version 9.0.0-milestone18version 9.0.0-milestone19version 9.0.0-milestone2
and 23 more version 9.0.0-milestone20version 9.0.0-milestone13version 9.0.0-milestone22version 9.0.0-milestone23version 9.0.0-milestone24version 9.0.0-milestone25version 9.0.0-milestone26version 9.0.0-milestone27version 9.0.0-milestone3version 9.0.0-milestone4≥ 7.0.23 and ≤ 7.0.90version 9.0.0-milestone9version 9.0.0-milestone8version 9.0.0-milestone7version 9.0.0-milestone6version 9.0.0-milestone5≥ 8.5.0 and ≤ 8.5.33≥ 9.0.1 and ≤ 9.0.11version 9.0.0version 9.0.0-milestone1version 9.0.0-milestone10version 9.0.0-milestone11version 9.0.0-milestone12
Vulnerable NIST National Vulnerability Database
Apache Software Foundation Tomcat version 7.0.23 to 7.0.90version 8.5.0 to 8.5.33version 9.0.0.M1 to 9.0.11 Vulnerable CVE Program (cve.org) e CISA ADP
Canonical Ubuntu Linux version 14.04version 16.04 Vulnerable NIST National Vulnerability Database
Debian Debian Linux version 8.0 Vulnerable NIST National Vulnerability Database
Netapp Snap Creator Framework versions not specified by the source Vulnerable NIST National Vulnerability Database
Oracle Communications Application Session Controller version 3.8.0version 3.7.1 Vulnerable NIST National Vulnerability Database
Oracle Hospitality Guest Access version 4.2.0version 4.2.1 Vulnerable NIST National Vulnerability Database
Oracle Instantis Enterprisetrack version 17.1version 17.2version 17.3 Vulnerable NIST National Vulnerability Database
Oracle Retail Order Broker version 5.1version 5.2version 15.0 Vulnerable NIST National Vulnerability Database
Oracle Secure Global Desktop version 5.4 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Desktop version 7.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server version 7.0version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Aus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Eus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Tus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Workstation version 7.0 Vulnerable NIST National Vulnerability Database
Maven Org.apache.tomcat.embed:tomcat-embed-core ≥ 8.5.0 and < 8.5.34≥ 7.0.23 and < 7.0.91≥ 9.0.0 and < 9.0.12 Vulnerable GitHub Security Advisories

Attack characteristics

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

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

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
4.3 CVSS 3.0 Medium 2.8 1.4 nvd@nist.gov via NIST National Vulnerability Database
4.3 CVSS 3.0 Medium — — GitHub, Inc. via GitHub Security Advisories
4.3 CVSS 2.0 Medium 8.6 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-601 · Open Redirect

Other CVEs with this weakness →

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Detection templates (Nuclei)
Exploit-DB

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

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).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 15, 2026 · GitHub Security Advisories
  • Affected products added · maven/org.apache.tomcat.embed:tomcat-embed-core
    Oct 15, 2026 · GitHub Security Advisories
  • Affected products added · apache software foundation/apache tomcat
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • 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 · apache/tomcat, debian/debian linux, canonical/ubuntu linux, netapp/snap creator framework, redhat/enterprise linux deskt
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVSS changed · 4.3
    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
  • 2018
  • CVE published
    Oct 4, 2018 · apache

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

66 on the record

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor
Open redirect
same class
CWE-601
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
  • CVE-2026-59084 Insufficient Technical Documentation vulnerability in Apache Tomcat since the… Jul 14, 2026
  • CVE-2026-59083 Improper Handling of URL Encoding (Hex Encoding) vulnerability in Apache Tomcat's… Jul 14, 2026
  • CVE-2026-14355 ext/openssl: Memory corruption in openssl_encrypt with AES-WRAP-PAD Jul 3, 2026
  • CVE-2026-55956 Apache Tomcat: Security constraints for default servlet ignored method Jun 29, 2026
  • CVE-2026-55957 Apache Tomcat: Authentication bypass with JNDIRealm and GSSAPI authenticated bind 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-2018-11784 is "Apache Tomcat Open Redirect vulnerability", rated Medium. 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 4.3 describes technical severity. EPSS 97.68% 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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