CVE-2021-27876
An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2021-27876- CVSS 3.1
- 8.1 High
CVSS:3.1/AC:L/AV:N/A:N/C:H/I:H/PR:L/S:U/UI:N - Updated
- 2026-11-02
EUVDEUVD-2021-14614
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.
- Record
EUVD-2021-14614- CVSS 3.1
- 8.1 High
CVSS:3.1/AC:L/AV:N/A:N/C:H/I:H/PR:L/S:U/UI:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9j5v-h34p-h6g6
An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client...
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.
- Record
GHSA-9j5v-h34p-h6g6- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-287
- Updated
- 2026-11-02
CISA KEV No score
Veritas Backup Exec Agent File Access Vulnerability
Veritas Backup Exec (BE) Agent contains a file access vulnerability that could allow an attacker to specially craft input parameters on a data management protocol command to access files on the BE Agent machine.
- Record
CVE-2021-27876- Weakness
- CWE-287
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-27876- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:S/C:C/I:P/A:N - Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | Veritas Backup Exec Agent Remote Code Execution | 2021-03-01 |
| PoC in GitHub | wingerbijay/CVE-2021-27876 | 2026-06-18 |
| PoC in GitHub | hyderpwn/veritas-backup | 2026-08-27 |
History
| Recorded | Changed | Sources |
|---|---|---|
| exploitation, exploits | ||
| first indexed | CVE List, EUVD, GitHub Advisories, CISA KEV, Metasploit, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27876 is a high vulnerability (CVSS 8.1) in Veritas Backup Exec, published March 1, 2021. CISA lists it as known to be exploited, since April 7, 2023. EUVD reports exploitation since April 7, 2023. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 13.5%, the 96th percentile. No source names a fixed version.