What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2023-04-07
• EPSS: 64.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-03-01 · updated 2026-06-17

Description

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

How to fix

Upgrade to a fixed version: Veritas Backup Exec 21.2. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html
• https://www.veritas.com/content/support/en_US/security/VTS21-001#issue1
• http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html
• https://www.veritas.com/content/support/en_US/security/VTS21-001#issue1
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27877

Get alerted when CVE-2021-27877 or the next vulnerability affects your stack