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CVE-2021-34741

HIGH CVSS: 7.5 Published: 2021-11-04 Modified: 2026-06-17

Description

A vulnerability in the email scanning algorithm of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to perform a denial of service (DoS) attack against an affected device. This vulnerability is due to insufficient input validation of incoming emails. An attacker could exploit this vulnerability by sending a crafted email through Cisco ESA. A successful exploit could allow the attacker to exhaust all the available CPU resources on an affected device for an extended period of time, preventing other emails from being processed and resulting in a DoS condition.

Affected Platforms

Cisco M390XCisco M690Cisco M170Cisco S395Cisco M190Cisco S695Cisco AsyncosCisco M390Cisco M380Cisco M680

Weakness Type

CWE-770, CWE-770

References