What is the CVSS score of CVE-2026-21667?

CVE-2026-21667 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.4%.

Which versions of Veeam Backup Replication are affected by CVE-2026-21667?

A critical vulnerability in our Backup Server allows any authenticated domain user to execute remote code, potentially compromising our entire backup infrastructure and enabling data exfiltration or…

How to fix or mitigate CVE-2026-21667?

Within 24 hours: Isolate the Backup Server from the network or restrict domain user access to emergency personnel only; audit recent backup server logs for suspicious activity. Within 7 days: Implement network segmentation to limit domain user connectivity to the Backup Server; deploy additional monitoring on backup infrastructure for anomalous activity. Within 30 days: Coordinate with vendor for patched software release; evaluate alternative backup solutions if patch timeline is unacceptable; conduct forensic analysis to detect any prior exploitation.

Veeam Backup Replication CVE-2026-21667

CRITICAL

Improper Access Control (CWE-284)

2026-03-12 support@hackerone.com

Authentication Bypass RCE Veeam Backup Replication Veeam

9.9

CVSS 3.1 · NVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

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

A second RCE vulnerability in Veeam Backup & Replication allows any authenticated domain user to execute code on the Backup Server with scope change. Same impact as CVE-2026-21666 but through a different attack vector.

Technical ContextAI

Similar to CVE-2026-21666, improper access controls (CWE-284) allow a low-privileged domain user to execute arbitrary code on the Veeam Backup Server with scope change. This represents a separate code path but the same fundamental access control failure.