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

> CVE-2021-27877: Veritas Backup Exec Agent Improper Authentication Vulnerability. CVSS 8.2 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2021-27877
Last updated: 2025-10-21T23:25:53Z

- Published: 2021-03-01 21:49 UTC · Updated: 2025-10-21 23:25 UTC · Assigner: mitre
- CVSS: 8.2 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AC:L/AV:N/A:N/C:H/I:L/PR:N/S:U/UI:N
- EPSS: 64.9%, 99th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2023-04-07, federal due date 2023-04-28, ransomware use: Known

## 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.

## CISA required action

Apply updates per vendor instructions.

## Affected vendors and products

- Veritas: Backup Exec Agent

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2021-27877)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2021-27877)
- [http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html](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.veritas.com/content/support/en_US/security/VTS21-001#issue1)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2021-27877 · Markdown: https://rewindex.com/cve/CVE-2021-27877.md · JSON: https://rewindex.com/api/v1/cves/CVE-2021-27877 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:05:26.047Z