CVE-2021-1566

HIGH

Cisco AsyncOS - SSL/TLS Man-in-the-Middle

Title source: llm
STIX 2.1

Description

A vulnerability in the Cisco Advanced Malware Protection (AMP) for Endpoints integration of Cisco AsyncOS for Cisco Email Security Appliance (ESA) and Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to intercept traffic between an affected device and the AMP servers. This vulnerability is due to improper certificate validation when an affected device establishes TLS connections. A man-in-the-middle attacker could exploit this vulnerability by sending a crafted TLS packet to an affected device. A successful exploit could allow the attacker to spoof a trusted host and then extract sensitive information or alter certain API requests.

References (1)

Core 1

Scores

CVSS v3 7.4
EPSS 0.0013
EPSS Percentile 31.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-295 CWE-296
Status published
Products (3)
cisco/asyncos < 12.5.3-035
cisco/email_security_appliance
cisco/web_security_appliance
Published Jun 16, 2021
Tracked Since Feb 18, 2026