What’s Vulnerable › Vulnerabilities
CVE-2019-1983: Cisco Email Security Appliance and Cisco Content Security Management Appliance Denial of Service Vulnerability
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.9% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-09-23 · updated 2026-06-17
- Weakness: CWE-20
Description
A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) and Cisco Content Security Management Appliance (SMA) could allow an unauthenticated, remote attacker to cause repeated crashes in some internal processes that are running on the affected devices, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient input validation of email attachments. An attacker could exploit this vulnerability by sending an email message with a crafted attachment through an affected device. A successful exploit could allow the attacker to cause specific processes to crash repeatedly, resulting in the complete unavailability of both the Cisco Advanced Malware Protection (AMP) and message tracking features and in severe performance degradation while processing email. After the affected processes restart, the software resumes filtering for the same attachment, causing the affected processes to crash and restart again. A successful exploit could also allow the attacker to cause a repeated DoS condition. Manual intervention may be required to recover from this situation.
Affected products
- Cisco Asyncos: before 11.0.1-161; from 12.0 through 12.5.0-633; before 11.0.3-251; from 12.0 before 12.5.0-059 — fixed in 11.0.1-161, 11.0.3-251, 12.5.0-059
- Cisco Content Security Management Appliance (SMA): 11.4.0-812
- Cisco Email Security Appliance (ESA): 11.0.1-hp5-602, 11.1.0-404
How to fix
Upgrade to a fixed version: Cisco Asyncos 11.0.1-161, 11.0.3-251, 12.5.0-059. Check the vendor advisory for mitigations.
References
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-sma-dos
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-sma-dos
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