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Forticlient Endpoint Management ServerApplication · Fortinet

CVE-2021-24019

CRITICAL · 9.8 CVSS v3.1 Published 2021-10-06
Fix available
A fix is available. Upgrade to 6.2.9 / 6.4.2 or later.
See remediation →
100/100
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
An insufficient session expiration vulnerability [CWE- 613] in FortiClientEMS versions 6.4.2 and below, 6.2.8 and below may allow an attacker to reuse the unexpired admin user session IDs to gain admin privileges, should the attacker be able to obtain that session ID (via other, hypothetical attacks)

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

FortiClientEMS contains an insufficient session expiration vulnerability (CWE-613) where admin session IDs remain valid even after logout or expected timeout. An attacker who obtains a valid admin session ID through separate attacks can reuse it to authenticate and gain full admin privileges on the management console.

MitigationUpgrade FortiClientEMS to version 6.4.3 or 6.2.9 or later. Until patching is feasible, implement strict session management controls and monitor for unauthorized admin access.

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
Forticlient Endpoint Management ServerApplication
Affected:< 6.2.9>= 6.4.0, < 6.4.2

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. Identify FortiClientEMS version
    Access the FortiClientEMS management console and navigate to the System Settings or About page to view the installed software version. Alternatively, check the installer or system information where FortiClientEMS is hosted.
    Affected if The displayed version is less than 6.2.9, or is 6.4.0, 6.4.1, or between 6.4.0 and 6.4.2 (exclusive).
  2. Compare version against affected ranges
    Verify the exact version number obtained from the previous step against the vulnerable ranges: versions below 6.2.9, and versions 6.4.0 through 6.4.1 are affected.
    Affected if The installed version falls into any of these ranges: < 6.2.9 OR (>= 6.4.0 AND < 6.4.2).
  3. Verify session invalidation behavior
    If you have admin access, log in to the FortiClientEMS console, note the session, then log out. Attempt to reuse the previous session identifier or token to authenticate again.
    Affected if The session remains valid after logout, allowing re-authentication with the old session ID.
  4. Check session timeout configuration
    Navigate to the admin session or timeout settings in the FortiClientEMS management console under System Settings or Administration options.
    Affected if Session timeout is set to an excessively long duration, indefinite, or if there is no configurable session expiration mechanism.

A user is affected if FortiClientEMS is running version 6.4.0 through 6.4.1, or any version below 6.2.9, and the admin session remains usable after logout.

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 6.2.9 / 6.4.2 or later
Fixed in 6.2.96.4.2
Interim mitigation

Upgrade FortiClientEMS to version 6.4.3 or 6.2.9 or later. Until patching is feasible, implement strict session management controls and monitor for unauthorized admin access.

Recommended fix High confidence

FortiClient EMS 6.2.9 or 6.4.2 or later

  1. 1. Identify the current FortiClient Endpoint Management Server version via the GUI (System Settings > Firmware) or CLI (get system status)
  2. 2. Navigate to the Fortinet Support Portal (support.fortinet.com) and download the fixed version: 6.2.9 or 6.4.2 (or later)
  3. 3. Back up the current EMS configuration from System Settings > Backup
  4. 4. Initiate the firmware upgrade via System Settings > Firmware or via CLI using the execute restore command
  5. 5. After upgrade, verify the version and confirm admin sessions properly expire
  6. 6. As a precaution, invalidate all existing admin sessions by resetting admin passwords
Caveat Review release notes for any configuration changes or deprecated features between your current version and the target fixed version before upgrading

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

Fix this in Forticlient Endpoint Management Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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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-2021-24019 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
  • 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