Security readout for executives and security teams
Plain-English summary
This flaw could let an outside sender bypass Cisco ESA message filters and place script content inside an email body. The script is not executed by default, but the control failure weakens an email security gateway that organizations rely on to enforce filtering policy.
Executive priority
Treat as a moderate-priority email security control weakness. It does not indicate automatic malware execution, but it can undermine gateway filtering and increase risk from malicious email reaching users.
Technical view
Cisco AsyncOS for Cisco ESA improperly validates certain email fields during message scanning. A remote unauthenticated attacker could send a crafted email to a protected recipient, bypass configured filters, and inject scripting code into the email body. CVSS v3.0 is 5.8, medium severity.
Likely exposure
Exposure is limited to Cisco Email Security Appliance deployments running the affected AsyncOS version identified in the bundle: 11.1.2-023. Organizations without Cisco ESA, or not using that version, are not shown affected by these sources.
Exploitation context
The source bundle does not show known active exploitation, and CVE is not listed as KEV. Exploitation requires delivery of a crafted email to a protected recipient. Script execution depends on the recipient email client allowing scripts in email content.
Researcher notes
The evidence supports a filter-bypass and script-injection condition in ESA message scanning caused by improper input validation. The bundle does not provide exploit samples, fixed version details, or observed exploitation evidence.
Mitigation direction
- Inventory Cisco ESA appliances and confirm AsyncOS versions.
- Check Cisco's advisory for fixed releases or workarounds, then follow vendor guidance.
- Prioritize upgrade planning for any ESA running 11.1.2-023.
- Ensure email clients do not execute scripts contained in messages.
- Review content filter rules for business-critical enforcement gaps.
Validation and detection
- Confirm whether any ESA reports AsyncOS 11.1.2-023.
- Verify Cisco ESA sits in front of protected mailboxes.
- Review ESA logs for messages that bypassed expected filters.
- Check mail client policy against script execution in email content.
- Document compensating controls until vendor remediation is applied.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2019-1933 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.8MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20190703 Cisco Email Security Appliance Content Filter Bypass VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.