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CVE-2017-3800 Cisco CVE debrief

CVE-2017-3800 is a Cisco AsyncOS issue in the content scanning engine for Cisco Email Security Appliances (ESA). If the appliance is configured to apply message or content filters to incoming email attachments, a remote unauthenticated attacker may be able to bypass those filters. Cisco and NVD list fixed releases and affected versions for ESA deployments on both virtual and hardware platforms.

Vendor
Cisco
Product
CVE-2017-3800
CVSS
MEDIUM 5.8
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-26
Original CVE updated
2026-05-13
Advisory published
2017-01-26
Advisory updated
2026-05-13

Who should care

Cisco ESA administrators, email security teams, and incident responders responsible for attachment filtering or message/content filtering on Cisco AsyncOS appliances should treat this as relevant, especially where ESA is used as a primary inbound email control.

Technical summary

The vulnerability affects the content scanning engine in Cisco AsyncOS Software for Cisco Email Security Appliances. In the affected configuration, incoming attachments may evade configured message or content filters, allowing a remote unauthenticated attacker to bypass intended filtering behavior. The supplied NVD record classifies the issue as CVSS v3.0 5.8/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N and maps it to CWE-20.

Defensive priority

Medium. The issue does not indicate confidentiality or availability impact, but it can weaken email security enforcement by letting content pass filters that are expected to inspect attachments.

Recommended defensive actions

  • Upgrade Cisco AsyncOS for Email Security Appliances to a fixed release identified by Cisco and NVD, such as 10.0.1-083 or 10.0.1-087.
  • Check whether your ESA deployment applies message filters or content filters to incoming email attachments, since that is the vulnerable use case described in the source record.
  • Inventory ESA versions against the known affected releases listed in the NVD metadata, including 9.7.1-066, 9.7.1-HP2-207, and 9.8.5-085.
  • Review the Cisco advisory reference in the supplied sources before scheduling remediation and confirm the upgrade path for your appliance model.
  • After updating, validate that attachment filtering and related message/content filter behavior is functioning as expected.

Evidence notes

This debrief is based only on the supplied NVD record and Cisco-referenced advisory links. The source metadata identifies the vulnerable product family, affected versions, fixed releases, CVSS vector, and CWE-20. No exploit code, reproduction steps, or unsupported operational claims are included.

Official resources

CVE published on 2017-01-26. The supplied Cisco advisory reference in the source metadata is dated 2017-01-18.