high Known exploitedREV. 01

CVE-2021-27876Veritas Backup Exec — any file, with system privileges

A weakness in a legacy authentication scheme lets an attacker finish the login to a Backup Exec agent, and a crafted data management command then reads any file on that machine with system privileges. Fixed in 21.2.

YOUR NEXT MOVE

Upgrade Backup Exec to 21.2 or later, and keep agent ports on an internal network. Ransomware crews went in through these agents, backups and all.

Read the risk

THE VITAL STATS
CVSS score
8.1/ 10
CVSS v3.1
EPSS probability
14%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2021-03-01
Added to KEV
2023-04-07
Exploit published
Yes
Confidence
medium
Kill chain
collection
MITRE ATT&CK
T1078
Severity
high

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

Attacker needsNetwork access to a Backup Exec agent.

Fixed inVeritas Backup Exec >= 21.2

Behind the card

4 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-09-24scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-24scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-24scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-24claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2021-27876 · CRDS 0.1 · Issued 2026-09-24