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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2021. Known ransomware use
Manageengine Adselfservice PlusApplication · Zohocorp

CVE-2021-40539

CRITICAL · 9.8 CVSS v3.1 Published 2021-09-07
Fix available
A fix is available. Upgrade to 6.1 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

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
Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.

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

Zoho ManageEngine ADSelfService Plus version 6113 and prior contains a vulnerability in the REST API that allows authentication bypass. Successful exploitation enables an unauthenticated attacker to execute arbitrary code remotely on the affected system.

MitigationUpgrade Zoho ManageEngine ADSelfService Plus to a version newer than 6113. Additionally, given active exploitation in the wild, perform thorough forensic analysis to check for signs of compromise.

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
Manageengine Adselfservice PlusApplication
Affected:< 6.1= 6.1

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. Confirm ADSelfService Plus is installed
    Check for the service process or installation directory. On Windows, look for 'ADSelfService Plus' in services.msc or check C:\ManageEngine\ADSelfService Plus. On Linux, check /opt/manageengine/ADSelfService Plus or run 'ps -ef | grep -i adselfservice'.
    Affected if The product is present on the system
  2. Identify the installed version
    Access the About page in the admin console (typically http://localhost:8888/about.jsp) or check the version file in the installation directory. On Windows, check C:\ManageEngine\ADSelfService Plus\build.txt or similar build info file. On Linux, check /opt/manageengine/ADSelfService Plus/build.txt.
    Affected if Version number is 6113 or lower, or displays as 6.1 or lower
  3. Compare version to affected range
    Verify if the installed version falls within < 6.1 or = 6.1 (or build number <= 6113). Note that version 6114 and later are not affected.
    Affected if Version is 6113 or prior, or 6.1 or earlier build
  4. Check if REST API is enabled and accessible
    Attempt to access the REST API authentication endpoint. The vulnerable endpoint is typically /api/internal/login. Use curl or a browser to request http://<server>:8888/api/internal/login without providing credentials.
    Affected if The API endpoint responds without requiring authentication, indicating the bypass is present
  5. Verify unauthenticated access to admin resources
    After checking the login endpoint, verify if unauthenticated access to admin functions is possible. The vulnerability allows gaining administrative access through the authentication bypass.
    Affected if Unauthenticated access to admin API functions is successful

The system is affected if ADSelfService Plus version 6113 or prior (or version 6.1 or earlier) is installed and the REST API endpoint is accessible without authentication.

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.

dbcve · scoped
Upgrade available Upgrade to 6.1 or later
Fixed in 6.1
Vendor patch www.manageengine.com →
Interim mitigation

Upgrade Zoho ManageEngine ADSelfService Plus to a version newer than 6113. Additionally, given active exploitation in the wild, perform thorough forensic analysis to check for signs of compromise.

Recommended fix High confidence

ADSelfService Plus build 6114 or later (6.1 SP 6114)

  1. 1. Download the latest version of ManageEngine ADSelfService Plus from the official ManageEngine website
  2. 2. Back up the current ADSelfService Plus installation including the database and configuration files
  3. 3. Stop the ADSelfService Plus service before performing the upgrade
  4. 4. Install the updated version (build 6114 or later) following the standard upgrade procedure
  5. 5. Start the ADSelfService Plus service after installation completes
  6. 6. Verify the upgrade by checking the build number in the About section of the admin console
  7. 7. Confirm that the REST API authentication bypass vulnerability is resolved by attempting to access the REST API without valid credentials (should be denied)
Caveat Review release notes for any configuration or feature changes between versions; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Manageengine Adselfservice Plus Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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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-2021-40539 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