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Vulnerability record · CVE-2019-1947 · published 23 September 2020

CVE-2019-1947: Cisco email security appliance improper input validation vulnerability

Cisco · Email Security Appliance

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause the CPU utilization to increase to 100 percent, causing a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of email messages that contain large attachments. An attacker could exploit this vulnerability by sending a malicious email message through the targeted device. A successful exploit could allow the attacker to cause a permanent DoS condition due to high CPU utilization. This vulnerability may require manual intervention to recover the ESA.

8.6 CVSS 3.1 High EPSS 1.9% · top 20.9% CWE-20 · Improper input validation
8.6CVSS 3.1 base score, v2 7.8
1.9%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause the CPU utilization to increase to 100 percent, causing a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of email messages that contain large attachments. An attacker could exploit this vulnerability by sending a malicious email message through the targeted device. A successful exploit could allow the attacker to cause a permanent DoS condition due to high CPU utilization. This vulnerability may require manual intervention to recover the ESA.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-dos Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-dos Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-1947), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.