Bw Calendar EngineApplication · Apereo

CVE-2018-1000836

CRITICAL · 9.0 CVSS v3.0 Published 2018-12-20
Fix available
A fix is available. Upgrade to after 3.12.0 or later.
See remediation →
99/100
Remediation priority · Urgent
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
bw-calendar-engine version <= bw-calendar-engine-3.12.0 contains a XML External Entity (XXE) vulnerability in IscheduleClient XML Parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via Man in the Middle or malicious server.

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

The bw-calendar-engine component versions 3.12.0 and below contain an XML External Entity (XXE) vulnerability in the IscheduleClient XML Parser. This XXE flaw allows an attacker who can perform a man-in-the-middle attack or control a server responding to the IscheduleClient to inject malicious XML containing external entity references, enabling disclosure of sensitive files from the host system, denial of service, SSRF attacks for internal network reconnaissance, and port scanning.

MitigationDisable XML external entity (XXE) processing in the IscheduleClient XML Parser configuration by disabling DTD processing and blocking external entity declarations. Validate and sanitize all XML input from untrusted sources.

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
Bw Calendar EngineApplication
Affected:<= 3.12.0

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
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

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. Identify if bw-calendar-engine is installed
    Search for the bw-calendar-engine library or component in your application dependencies, classpath, or deployed artifacts. Check build files (pom.xml, package.json, Gradle files), WAR/EAR contents, or application lib directories.
    Affected if The bw-calendar-engine component is found in your environment
  2. Determine the installed version of bw-calendar-engine
    Locate the version information from the JAR manifest, dependency management system, or version file included with the component. Compare the version number to the affected range of 3.12.0 and below.
    Affected if The installed version is 3.12.0 or any earlier version
  3. Check if IscheduleClient is in use
    Search configuration files, application logs, or source code for references to IscheduleClient, Ischedule, or iSchedule protocols. Examine any XML parser configurations specific to calendar or scheduling functionality.
    Affected if IscheduleClient is configured or actively used by your application
  4. Verify XXE protection is enabled in the XML parser
    Inspect the XML parser configuration for the IscheduleClient to confirm whether external entity processing and DTD processing are disabled. Look for security-related parser settings such as disallowing DTDs, disabling external entities, or enabling safe XML processing modes.
    Affected if XXE protections are not explicitly configured or are disabled in the IscheduleClient XML parser settings

Your environment is affected if bw-calendar-engine version 3.12.0 or lower is installed AND IscheduleClient is being used AND XML external entity protection is not enabled in the parser configuration.

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 3.12.0
Interim mitigation

Disable XML external entity (XXE) processing in the IscheduleClient XML Parser configuration by disabling DTD processing and blocking external entity declarations. Validate and sanitize all XML input from untrusted sources.

Fix this in Bw Calendar Engine Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2018-1000836 in production — separate from our analysis above.

No notes yet

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data