---
id: "CVE-2021-27876"
kind: "vulnerability"
aliases: ["CVE-2021-27876"]
title: "An issue was discovered in Veritas Backup Exec before 21.2"
severity: "high"
cvss: 8.1
epss: null
exploited: true
status: "open"
category: "other"
products: [{"name": "Veritas Backup Exec Agent", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "veritas backup exec", "fixed": ["21.2"], "affected": "< 21.2", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["backup-servers", "exploited", "other", "ransomware", "veritas-backup-exec", "windows"]
not_affected_if: ["unknown"]
published_at: "2021-03-01T22:15:14+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27876", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-27876", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# An issue was discovered in Veritas Backup Exec before 21.2

Veritas Backup Exec Agent has a file access flaw that lets an attacker craft parameters on a data management protocol command to read files on the agent machine. CISA lists it as actively exploited, and the tags include ransomware use.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Veritas Backup Exec Agent affected ? fixed ?
- vendor:veritas backup exec affected < 21.2 fixed 21.2

## Fix

Apply the vendor updates per Veritas instructions (CISA required action); exact fixed version unknown from sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27876
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-27876

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_