CVE-2019-1983: Cisco Asyncos

Medium severity, CVSS 5.3. EPSS: 1.9% chance of exploitation in the next 30 days.

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 (fixed in 11.0.1-161); from 12.0, up to and including 12.5.0-633; before 11.0.3-251 (fixed in 11.0.3-251); from 12.0, before 12.5.0-059 (fixed in 12.5.0-059)
• Cisco Content Security Management Appliance: version 11.4.0-812 only
• Cisco Email Security Appliance: version 11.0.1-hp5-602 only; version 11.1.0-404 only

Published 2020-09-23. Last modified 2026-06-17.