dbcve.org
Tomcat Jk ConnectorWeb server / proxy · Apache

CVE-2018-11759

HIGH · 7.5 CVSS v3.0 Published 2018-10-31
Fix available
A fix is available. Upgrade to after 1.2.44 or later.
See remediation →
84/100
Remediation priority · High
High EPSS Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The Apache Web Server (httpd) specific code that normalised the requested path before matching it to the URI-worker map in Apache Tomcat JK (mod_jk) Connector 1.2.0 to 1.2.44 did not handle some edge cases correctly. If only a sub-set of the URLs supported by Tomcat were exposed via httpd, then it was possible for a specially constructed request to expose application functionality through the reverse proxy that was not intended for clients accessing the application via the reverse proxy. It was also possible in some configurations for a specially constructed request to bypass the access controls configured in httpd. While there is some overlap between this issue and CVE-2018-1323, they are not identical.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A path normalization vulnerability in Apache Tomcat JK Connector (mod_jk) 1.2.0 to 1.2.44 allows specially crafted requests to either expose unintended application functionality through the reverse proxy or bypass httpd access controls. The normalization code fails to handle edge cases when matching requests to the URI-worker map.

MitigationUpgrade mod_jk to version 1.2.45 or later, and review URI-worker mappings and httpd access control configurations to ensure only intended endpoints are exposed through the reverse proxy.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Tomcat Jk ConnectorWeb server / proxy
Affected:>= 1.2.0, <= 1.2.44
Debian LinuxOperating system
Affected:= 8.0= 9.0
Jboss Core ServicesApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if mod_jk is installed
    Run 'httpd -M' or 'apache2ctl -M' and look for the 'jk_module' or search for 'mod_jk' in the Apache modules directory (typically /usr/lib/apache2/modules/ or /etc/httpd/modules/)
    Affected if mod_jk (jk_module) appears in the loaded modules list or the mod_jk.so file exists in the Apache modules directory
  2. Determine the mod_jk version
    Run 'httpd -v' or 'apache2ctl -V' to get Apache version, then check the mod_jk version by running 'strings mod_jk.so | grep -i "JK_VERSION"' or checking the file metadata if available
    Affected if The mod_jk version is between 1.2.0 and 1.2.44 inclusive (the output will show a version number in this range)
  3. Verify the worker configuration file
    Locate the worker configuration file (commonly workers.properties or jk.conf) typically in /etc/apache2/, /etc/httpd/conf/, or within the Apache config directory; inspect the URI-worker mappings defined in the config
    Affected if URI-worker mappings exist that route requests through the JK connector to backend Tomcat workers (this confirms mod_jk is actively being used)
  4. Check if path normalization affects your exposed endpoints
    Review the URI-worker map for all defined mappings (JkMount orJkUnMount directives); test edge case URI patterns such as those with multiple slashes, encoded characters, or path traversal sequences like /.. to see if unintended endpoints become accessible
    Affected if Any URI-worker mappings exist and the application relies on the reverse proxy to restrict access to specific endpoints (the vulnerability allows bypassing these restrictions)

You are affected if mod_jk (jk_module) is loaded in Apache and its version is 1.2.0 through 1.2.44, especially if you rely on URI-worker mappings or httpd access controls to restrict which backend endpoints are accessible through the reverse proxy.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 1.2.44
Interim mitigation

Upgrade mod_jk to version 1.2.45 or later, and review URI-worker mappings and httpd access control configurations to ensure only intended endpoints are exposed through the reverse proxy.

Fix this in Tomcat Jk Connector Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-11759 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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