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FortimailApplication · Fortinet

CVE-2021-24015

HIGH · 8.8 CVSS v3.1 Published 2021-07-12
Fix available
A fix is available. Upgrade to 6.0.11 / 6.2.7 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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 improper neutralization of special elements used in an OS Command vulnerability in the administrative interface of FortiMail before 6.4.4 may allow an authenticated attacker to execute unauthorized commands via specifically crafted HTTP requests.

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

This is an OS command injection vulnerability in FortiMail's administrative web interface. An authenticated attacker can send specially crafted HTTP requests containing malicious OS commands that the application will execute with the privileges of the web server process. The vulnerability affects versions prior to 6.4.4.

MitigationUpgrade FortiMail to version 6.4.4 or later to remediate this vulnerability. If immediate patching is not possible, restrict administrative interface access to trusted IP addresses via firewall rules or VPN.

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
FortimailApplication
Affected:>= 5.4.0, <= 5.4.12>= 6.0.0, < 6.0.11>= 6.2.0, < 6.2.7>= 6.4.0, < 6.4.4

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/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 FortiMail installation and version
    Access the FortiMail administrative web interface and navigate to System > Status or use CLI command 'get system status' to retrieve the firmware version
    Affected if Version falls within 5.4.0-5.4.12, 6.0.0-6.0.10, 6.2.0-6.2.6, or 6.4.0-6.4.3
  2. Verify administrative web interface accessibility
    Check if TCP port 443 or 80 on the FortiMail device is responding to HTTP/HTTPS requests from untrusted networks
    Affected if The admin interface is reachable from networks that are not trusted or contain untrusted users
  3. Confirm authentication is enabled for admin interface
    Verify that admin account authentication is not disabled or bypassed for the web interface by reviewing admin user configuration in System > Admin > Administrators
    Affected if Administrative users can authenticate to the web interface (this is the default and typical configuration)
  4. Check for suspicious admin activity or command injection artifacts
    Review FortiMail logs under Log & Report > Event Log for any entries containing unusual command patterns, shell executions, or unexpected system commands initiated from the web interface
    Affected if Logs show execution of OS commands that were not initiated by legitimate administrative actions

The environment is affected if FortiMail version is in any of the vulnerable ranges AND the administrative web interface is accessible to an authenticated attacker.

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 6.0.11 / 6.2.7 / 6.4.4 or later
Fixed in 6.0.116.2.76.4.4
Interim mitigation

Upgrade FortiMail to version 6.4.4 or later to remediate this vulnerability. If immediate patching is not possible, restrict administrative interface access to trusted IP addresses via firewall rules or VPN.

Recommended fix High confidence

FortiMail 6.4.4 or later (or latest 6.4.x stable release for your branch)

  1. 1. Identify the current FortiMail version by logging into the administrative interface or running: get system status
  2. 2. Determine the appropriate upgrade path based on your current version (e.g., 5.4.x -> 6.0.11 -> 6.2.7 -> 6.4.4, or jump to latest 6.4.x if supported)
  3. 3. Backup the FortiMail configuration via the web interface (System > Maintenance > Configuration) or CLI command: execute backup config tftp <filename > <tftp-server>
  4. 4. Review Fortinet's release notes for version 6.4.4 or later for any special upgrade considerations
  5. 5. Upload the firmware file via System > Firmware or via CLI: execute upload firmware <tftp-server> <filename>
  6. 6. Reboot the device to apply the new firmware
  7. 7. After upgrade, verify the system is running version 6.4.4 or later using: get system status
  8. 8. Verify the vulnerability is remediated by confirming the version is at or above the fixed release
Caveat Review Fortinet release notes for your specific upgrade path; major version jumps may require intermediate upgrades and configuration adjustments

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

Fix this in Fortimail Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

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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-2021-24015 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