CVE-2021-27878
Veritas Backup Exec Agent Command Execution Vulnerability
- Published
- Mar 1, 2021
- Updated
- Oct 21, 2025
- Assigning CNA
- mitre
- Evidence observed
- Apr 7, 2023
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HModerate · next 30 days
- Percentile
- 97.8%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
CISA Known Exploited
This CVE appears in the CISA Known Exploited Vulnerabilities catalog.
Summary
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.
Sources
1- CVE-2021-27876Exploit
Unauthenticated RCE exploit for Veritas Backup Exec Agent (CVE-2021-27876/77/78) — SHA auth bypass to SYSTEM via NDMP
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