CVE-2021-27876Known exploitationPublic exploitNetwork attack vector

Arbitrary file access via crafted protocol parameters

Published Mar 1, 2021 · Updated Oct 21, 2025

Arbitrary file access in Veritas Backup Exec Agent before 21.2 allows remote authenticated users to access files with System privileges. The agent's data management command processes crafted input parameters as arbitrary file requests under System authority. Reaching the command requires an authenticated agent connection, but the obsolete SHA scheme permits unauthorized completion of that authentication.

CVSS severity8.1
High
EPSS probability13.52%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file access in Veritas Backup Exec Agent before 21.2 allows remote authenticated users to access files with System privileges. The agent's data management command processes crafted input parameters as arbitrary file requests under System authority. Reaching the command requires an authenticated agent connection, but the obsolete SHA scheme permits unauthorized completion of that authentication.

The record

CVE
CVE-2021-27876
Published
Mar 1, 2021
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1005, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 1, 2021CVE publishedPublication date reported by the CVE source.
  2. 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

7.5NIST NVDAV:N/AC:L/Au:S/C:C/I:P/A:N
8.1VeritasCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

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
T1005Data from Local System
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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