AsyncosOperating system · Cisco
CVE-2025-20393
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 · uneditedA vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to execute arbitrary system commands on an affected device with root privileges. This vulnerability is due to insufficient validation of HTTP requests by the Spam Quarantine feature. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.
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 confidenceA command injection vulnerability in the Spam Quarantine feature of Cisco Secure Email Gateway allows unauthenticated remote attackers to execute arbitrary commands with root privileges via specially crafted HTTP requests due to insufficient input validation.
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
AsyncosOperating system
< 15.0.5-016>= 15.5, < 15.5.4-012>= 16.0, < 16.0.4-016< 15.0.2-007>= 15.5, < 15.5.4-007>= 16.0, < 16.0.4-010CVSS 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
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 checksWork through these to decide whether this CVE applies to you.
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Identify the device and AsyncOS versionLog into the Cisco Secure Email Gateway CLI and run the 'version' or 'show version' command to display the AsyncOS firmware version.Affected if The displayed AsyncOS version matches one of the affected ranges: < 15.0.5-016, >= 15.5 and < 15.5.4-012, >= 16.0 and < 16.0.4-016, < 15.0.2-007, >= 15.5 and < 15.5.4-007, or >= 16.0 and < 16.0.4-010.
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Confirm Spam Quarantine feature is enabledIn the CLI, run 'spamquarantine' or 'showspamquarantine' command, or access the web UI and navigate to Security Services > Spam Quarantine to verify if the feature is turned on.Affected if Spam Quarantine is enabled (status shows as 'Enabled' or 'On').
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Verify Spam Quarantine network accessibilityCheck the interface bindings for Spam Quarantine in the web UI under Network > Interfaces, or use the CLI 'listenerconfig' command to see which interfaces the Spam Quarantine listener is bound to, and confirm whether it is exposed to untrusted networks.Affected if Spam Quarantine is accessible from an untrusted or external network interface (not limited to internal/management networks only).
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Check for suspicious Spam Quarantine HTTP requestsReview the Spam Quarantine logs and mail logs (located in /var/log/ or accessible via the CLI 'grep' command) for unusual or encoded patterns in HTTP requests to the quarantine interface that may indicate exploitation attempts.Affected if Logs show unexpected HTTP request patterns, shell command strings, or unusual URL parameters sent to the Spam Quarantine endpoint.
You are affected if your Cisco Secure Email Gateway runs a vulnerable AsyncOS version AND the Spam Quarantine feature is enabled and accessible, regardless of network exposure.
Generated from the published advisory. Verify against your own configuration.
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 · scoped15.0.2-00715.0.5-01615.5.4-007
Apply the vendor patch from Cisco for AsyncOS Software addressing the Spam Quarantine HTTP request validation issue. If patches are unavailable, consider disabling the Spam Quarantine feature or restricting management interface access via network segmentation.
Minimum fixed versions: 15.0.5-016 for 15.0.x branch, 15.5.4-012 for 15.5.x branch, 16.0.4-016 for 16.0.x branch
- Identify the current AsyncOS version by running the version command in the CLI or checking the GUI dashboard
- Determine which version branch your device is running (15.0.x, 15.5.x, or 16.0.x)
- For 15.0.x devices: upgrade to version 15.0.5-016 or later
- For 15.5.x devices: upgrade to version 15.5.4-012 or later
- For 16.0.x devices: upgrade to version 16.0.4-016 or later
- Download the update from Cisco Secure Email Gateway software downloads (requires valid service contract)
- Schedule a maintenance window as the upgrade may cause brief service interruption
- Back up the current device configuration before applying the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Asyncos
Exploited in the wild — priority engagement
- Consultation4.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20393 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-20393 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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