What’s Vulnerable › Vulnerabilities

CVE-2021-27876: Veritas Backup Exec Agent File Access Vulnerability

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2023-04-07
• EPSS: 13.5% 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. 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. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.

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#issue2
• http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html
• https://www.veritas.com/content/support/en_US/security/VTS21-001#issue2
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27876

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