CVE-2021-27878: Veritas Backup Exec Agent Command Execution Vulnerability

High severity, CVSS 8.8. Actively exploited: in CISA KEV since 2023-04-07. EPSS: 24% chance of exploitation in the next 30 days.

An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. The attacker could use one of these commands to execute an arbitrary command on the system using system privileges.

Affected products

• Veritas Backup Exec: before 21.2 (fixed in 21.2)

Published 2021-03-01. Last modified 2026-06-17.