CVE-2021-27877
An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2021-27877- CVSS 3.1
- 8.2 High
CVSS:3.1/AC:L/AV:N/A:N/C:H/I:L/PR:N/S:U/UI:N - Updated
- 2026-11-02
EUVDEUVD-2021-14615
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.
- Record
EUVD-2021-14615- CVSS 3.1
- 8.2 High
CVSS:3.1/AC:L/AV:N/A:N/C:H/I:L/PR:N/S:U/UI:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-grhg-3w4v-cp2r
An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication...
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.
- Record
GHSA-grhg-3w4v-cp2r- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287
- Updated
- 2026-11-02
CISA KEV No score
Veritas Backup Exec Agent Improper Authentication Vulnerability
Veritas Backup Exec (BE) Agent contains an improper authentication vulnerability that could allow an attacker unauthorized access to the BE Agent via SHA authentication scheme.
- Record
CVE-2021-27877- Weakness
- CWE-287
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-27877- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - 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 | yashswarup12/CVE-2021-27877-PoC | 2026-07-02 |
| Nuclei | Veritas Backup Exec - Broken Authentication |
History
| Recorded | Changed | Sources |
|---|---|---|
| exploitation, exploits | ||
| first indexed | CVE List, EUVD, GitHub Advisories, CISA KEV, Metasploit, Nuclei, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27877 is a high vulnerability (CVSS 8.2) 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 64.9%, the 99th percentile. No source names a fixed version.