KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-27877

Backup Exec

Veritas / Backup Exec

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Severity
CVSS 8.2 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
64.9%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-27877 is an unauthenticated vulnerability affecting Veritas Backup Exec. An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Veritas / Backup Exec.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

An issue was discovered in Veritas Backup Exec before 21.2

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.

Published
01 Mar 2021
Exploitation Reported
07 Apr 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner metasploit malware cisa ransomware

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 07 Apr 2023

Independent exploitation attestation added to the KEV Intelligence record.

Used in malware

CISA

Recorded 07 Apr 2023

Malware families have been linked to exploitation of this CVE.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CISA First 2023-04-07 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/network/cves/2021/CVE-2021-27877.yaml 01 Jun 2026
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/veritas/beagent_sha_auth_rce.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

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

EPSS

64.9%

All CVSS Scores

CVSS v3.1 8.2 High

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

CVSS v2.0 7.5 High

AV:N/AC:L/Au:N/C:P/I:P/A:P

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Veritas Backup Exec - Broken Authentication

nuclei · Created Unknown

Veritas Backup Exec - Broken Authentication

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. Public PoC available

    Public proof-of-concept code published

  2. Nuclei template available

    Scanner coverage available

  3. Metasploit module available

    Exploit module available

  4. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. First public exploitation report

    Exploit observed in malware

  6. CVE published

    Vulnerability disclosed publicly

  7. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-27877

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-27877",
  "confidence": "Confirmed",
  "cvss_score": 8.2,
  "cvss_estimated": false,
  "epss_score": 0.6491,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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