Email Security ApplianceApplication · Cisco
CVE-2019-1933
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 email message scanning of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass configured filters on the device. The vulnerability is due to improper input validation of certain email fields. An attacker could exploit this vulnerability by sending a crafted email message to a recipient protected by the ESA. A successful exploit could allow the attacker to bypass configured message filters and inject arbitrary scripting code inside the email body. The malicious code is not executed by default unless the recipient's email client is configured to execute scripts contained in emails.
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 confidenceImproper input validation in Cisco AsyncOS Software's email message scanning component allows unauthenticated remote attackers to bypass configured message filters on the Email Security Appliance (ESA). By sending crafted email messages with specially malformed fields, attackers can inject arbitrary scripting code into email bodies that bypass the ESA's content filters.
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
Email Security ApplianceApplication
= 11.1.2-023CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N
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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Determine Cisco ESA AsyncOS versionAccess the ESA CLI and run the command to display the system version, typically 'version' or 'show version', or access the web interface System Administration > System Updates to view the installed AsyncOS version.Affected if The installed version is exactly 11.1.2-023.
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Verify email message scanning is enabledIn the ESA web interface, navigate to Mail Policies > Message Filters or use the CLI 'showfilters' command to confirm that message filters are configured and the content scanning component is active.Affected if Message filters are configured and the email scanning component is enabled.
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Confirm mail processing is activeCheck the ESA mail flow status via the CLI command 'mailconfig' or through the Monitor > Mail Flow Details section of the web interface to ensure inbound/outbound email processing is active.Affected if The ESA is actively processing email messages through its scanning component.
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Review filter bypass capabilityExamine configured message filters for any that handle HTML content, script tags, or attachment scanning. The vulnerability allows bypass of these filters when malformed email fields are received.Affected if Content filters that inspect or block scripting in emails are present in the filter configuration.
You are affected if your Cisco ESA runs exactly version 11.1.2-023 and has active message filters with email scanning enabled, as the vulnerability allows attackers to bypass those filters using malformed email fields containing script code.
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.
From vendor dataApply the vendor-provided security update for Cisco AsyncOS Software. As a defensive measure, ensure email clients are configured to disable script execution in emails and consider supplementary content filtering at other network layers.
Fix this in Email Security Appliance
Scoped from the published advisory
- Consultation4.0 h
- Implementation3.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-1933 — 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-2019-1933 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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- Version or environment caveats, and links to real fixes
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