CVE-2021-27878Known exploitationPublic exploitNetwork attack vector

System command execution via SHA authentication bypass

Published Mar 1, 2021 · Updated Oct 21, 2025

Command injection in Veritas Backup Exec Agent before 21.2 allows remote authenticated users to execute commands with system privileges. The agent accepts a data management protocol command after the obsolete SHA scheme improperly completes authentication for an unauthorized client. Network reachability to the agent is required; successful exploitation runs arbitrary commands as SYSTEM or root.

CVSS severity8.8
High
EPSS probability23.95%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Veritas Backup Exec Agent before 21.2 allows remote authenticated users to execute commands with system privileges. The agent accepts a data management protocol command after the obsolete SHA scheme improperly completes authentication for an unauthorized client. Network reachability to the agent is required; successful exploitation runs arbitrary commands as SYSTEM or root.

The record

CVE
CVE-2021-27878
Published
Mar 1, 2021
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 2023Exploitation reportedCISA Known Exploited Vulnerabilities catalog listing
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8VeritasCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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