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Veeam Backup Replication CVE-2026-21666

CRITICAL
Improper Access Control (CWE-284)
2026-03-12 support@hackerone.com
9.9
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
9.9 CRITICAL
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Analysis Generated
Mar 12, 2026 - 19:57 vuln.today
CVE Published
Mar 12, 2026 - 15:16 nvd
CRITICAL 9.9

DescriptionCVE.org

A vulnerability allowing an authenticated domain user to perform remote code execution (RCE) on the Backup Server.

AnalysisAI

Veeam Backup & Replication allows an authenticated domain user to achieve remote code execution on the Backup Server. With a scope change to CVSS 9.9, a compromised domain account can fully take over the backup infrastructure.

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Authenticate as domain user
Exploit
Send malicious RPC request to Backup Server
Execution
Trigger code execution vulnerability
Impact
Execute arbitrary commands with server privileges

Vulnerability AssessmentAI

Exploitation Authenticated domain user account required. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 9.9 (Critical). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A ransomware operator compromises a domain user account, then exploits this vulnerability to execute code on the Veeam server. They delete all backup copies before deploying ransomware across the domain, eliminating recovery options.
Remediation Apply Veeam security patches immediately. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Isolate the Backup Server from the domain and restrict network access to authorized administrators only; audit backup logs for suspicious activity. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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CVE-2026-21666 vulnerability details – vuln.today

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