CWE-538Weakness · CWE-538

CVE-2016-20024

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit 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
ZKTeco ZKTime.Net 3.0.1.6 contains an insecure file permissions vulnerability that allows unprivileged users to escalate privileges by modifying executable files. Attackers can exploit world-writable permissions on the ZKTimeNet3.0 directory and its contents to replace executable files with malicious binaries for privilege escalation.

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

ZKTeco ZKTime.Net 3.0.1.6 has insecure file permissions on the ZKTimeNet3.0 directory and its contents, allowing world-writable access. Unprivileged local users can replace executable files within this directory with malicious binaries to achieve privilege escalation to administrator or system level.

MitigationRestrict file permissions on the ZKTimeNet3.0 directory and contents by removing world-writable permissions and assigning appropriate ACLs limited to administrative users and the service account.

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 checks

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

  1. Verify ZKTeco ZKTime.Net installation and version
    Search the system for ZKTime.Net installation and confirm the version is 3.0.1.6. Check registry keys under HKLM\SOFTWARE\ZKTeco or look for the application in Add/Remove Programs.
    Affected if The installed version matches 3.0.1.6 exactly.
  2. Locate the ZKTimeNet3.0 directory
    Search for a directory named ZKTimeNet3.0 on the system, typically found within the ZKTeco ZKTime.Net installation path (commonly under Program Files or Program Files (x86)).
    Affected if The ZKTimeNet3.0 directory exists on the system.
  3. Check directory permissions for world-writable access
    Inspect the ACLs on the ZKTimeNet3.0 directory using icacls or a file permission auditing tool. Look for entries granting Write permissions to the Everyone group or the Users group.
    Affected if The directory permissions allow world-writable or group-writable access (Write permission granted to Everyone, Users, or other non-admin principals).
  4. Verify executable file permissions within the directory
    Examine individual .exe or .dll files inside the ZKTimeNet3.0 directory to confirm they are also world-writable. Use icacls <filename> to view specific file ACLs.
    Affected if Executable files within the directory are replaceable by unprivileged users due to overly permissive ACLs.

A user is affected if ZKTime.Net version 3.0.1.6 is installed and the ZKTimeNet3.0 directory and its contents have world-writable or group-writable permissions allowing unprivileged access.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict file permissions on the ZKTimeNet3.0 directory and contents by removing world-writable permissions and assigning appropriate ACLs limited to administrative users and the service account.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2016-20024 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-20024 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
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