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Secure Email GatewayApplication · Cisco

CVE-2024-20401

CRITICAL · 9.8 CVSS v3.1 Published 2024-07-17
Fix available
A fix is available. Upgrade to 15.5.1-055 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
A vulnerability in the content scanning and message filtering features of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to overwrite arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when file analysis and content filters are enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to replace any file on the underlying file system. The attacker could then perform any of the following actions: add users with root privileges, modify the device configuration, execute arbitrary code, or cause a permanent denial of service (DoS) condition on the affected device. Note: Manual intervention is required to recover from the DoS condition. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition.

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

A file overwrite vulnerability in Cisco Secure Email Gateway's content scanning and message filtering allows unauthenticated remote attackers to write to arbitrary filesystem locations by sending emails with specially crafted attachments. Successful exploitation enables root privilege escalation, arbitrary code execution, configuration modification, or permanent device DoS requiring TAC intervention.

MitigationApply Cisco's available patch or firmware update for CVE-2024-20401; until patched, consider disabling content scanning filters if operationally feasible or implementing additional network-level controls to limit exposure to untrusted email sources.

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
Secure Email GatewayApplication
Affected:< 15.5.1-055

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 Cisco Secure Email Gateway version
    Log into the email gateway CLI and run the `version` or `show version` command to display the installed firmware version.
    Affected if The displayed version is lower than 15.5.1-055 (for example, 15.0.1-xxx, 15.5.0-xxx, or any build below 055).
  2. Confirm content scanning filters are active
    In the email gateway GUI, navigate to Security Services > Content Scanning or use the CLI command `contentfilter` / `scanconfig` to view content scanning configuration.
    Affected if Content scanning filters are enabled and configured to process incoming email attachments.
  3. Check message filter rules
    In the GUI, go to Mail Policies > Message Filters or use the CLI command `filter` / `listfilters` to display active message filter rules.
    Affected if Message filters are defined and active, particularly any that perform attachment processing or file handling actions.

A Cisco Secure Email Gateway is affected if its firmware version is below 15.5.1-055 AND content scanning filters or message filters that handle attachments are enabled.

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 15.5.1-055 or later
Fixed in 15.5.1-055
Interim mitigation

Apply Cisco's available patch or firmware update for CVE-2024-20401; until patched, consider disabling content scanning filters if operationally feasible or implementing additional network-level controls to limit exposure to untrusted email sources.

Recommended fix High confidence

Upgrade to Cisco Secure Email Gateway version 15.5.1-055 or later

  1. 1. Check current Cisco Secure Email Gateway version by navigating to System Administration > About IronPort page or running the version command
  2. 2. Schedule a maintenance window for the upgrade (this may cause brief service interruption)
  3. 3. Back up the current device configuration using the savedconfig command or through the web interface
  4. 4. Download the firmware upgrade image (version 15.5.1-055 or later) from the Cisco Software Downloads page on sec.cloudapps.cisco.com
  5. 5. Upload the upgrade image via the web interface (System Administration > Upgrade) or CLI
  6. 6. Run the upgrade command and wait for the process to complete
  7. 7. Reboot the device when prompted
  8. 8. After reboot, verify the new version shows 15.5.1-055 or later using the version command
Caveat Standard upgrade may cause brief email processing delays; ensure backup of configuration before proceeding

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

Fix this in Secure Email Gateway Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2024-20401 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