CVE-2016-20026
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 · uneditedZKTeco ZKBioSecurity 3.0 contains hardcoded credentials in the bundled Apache Tomcat server that allow unauthenticated attackers to access the manager application. Attackers can authenticate with hardcoded credentials stored in tomcat-users.xml to upload malicious WAR archives containing JSP applications and execute arbitrary code with SYSTEM privileges.
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 confidenceZKTeco ZKBioSecurity 3.0 ships with a bundled Apache Tomcat server containing hardcoded credentials stored in tomcat-users.xml. Attackers can use these credentials to access the unauthenticated Tomcat manager application and upload malicious WAR archives containing JSP web shells, achieving arbitrary code execution with SYSTEM privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checksWork through these to decide whether this CVE applies to you.
-
Identify ZKBioSecurity 3.0 installationLook for ZKBioSecurity installation directories (commonly under C:\Program Files\ZKTeco\ or C:\ZKTeco\) or check for running services named 'ZKBioSecurity' or similar in Windows Services or Unix init scriptsAffected if ZKBioSecurity 3.0 is installed on the system
-
Locate bundled Apache TomcatWithin the ZKBioSecurity installation directory, look for a 'tomcat', 'ApacheTomcat', or similar subdirectory that contains the Tomcat server structure (bin, conf, webapps folders)Affected if A bundled Tomcat server exists within the ZKBioSecurity installation
-
Locate and inspect tomcat-users.xmlFind the conf/tomcat-users.xml file within the bundled Tomcat directory and open it in a text editor to examine its contents for user entriesAffected if The file contains <user> entries with hardcoded username and password attributes, especially for roles like 'manager-gui' or 'admin-gui'
-
Check for default manager applicationWithin the bundled Tomcat, verify the presence of the manager webapp in the webapps directory (look for 'manager' folder or manager.war) and check conf/Catalina/localhost/manager.xml for context configurationAffected if The manager application is deployed and available in the webapps directory
-
Test manager interface accessibilityAttempt to access the Tomcat manager interface via HTTP/HTTPS at the typical path (such as /manager/html) on the port where the bundled Tomcat is running - check if authentication is required or if access is blockedAffected if The manager interface is accessible without authentication or using the hardcoded credentials found in tomcat-users.xml
A user is affected if ZKBioSecurity 3.0 is installed with its bundled Tomcat server containing hardcoded credentials in tomcat-users.xml that allow unauthenticated access to the manager application.
Generated from the published advisory. Verify against your own configuration.
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 dataRemove or change the hardcoded Tomcat credentials in tomcat-users.xml, disable the manager application if unused, and restrict manager interface access via network segmentation or firewall rules to prevent unauthenticated access.
- Consultation4.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,728.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-20026 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2016-20026 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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