CVE-2021-27877: Veritas Backup Exec Agent Improper Authentication Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2023-04-07. EPSS: 64.9% chance of exploitation in the next 30 days.

An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of these. This authentication scheme is no longer used in current versions of the product, but hadn't yet been disabled. An attacker could remotely exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.

Affected products

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

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