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01 Record

CVE-2026-21666

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

CriticalPUBLISHEDCNA: hackerone
CNA base score10.0 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

02 Description

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

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
1.17% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 67.4% of scored records. A rank, not a probability.
NVD base score
8.8 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD analysis status
Analyzed. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-03-12 15:09Z7 MO AGO
Last updated
2026-03-13 03:55Z7 MO AGO
Reserved
2026-01-02
Assigning CNA
hackerone
Record state
PUBLISHED
Severity
Critical (CVSS 10.0)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weaknesses
  • CWE-284Improper Access ControlPillar
Data version
5.2
Document digest
9fd31634189bdf4ef8c5c57c87ffd9b48f5c65bfd4f8c5816823f1dfd057742e

05 Affected products

VendorProductVersionsPlatforms
VeeamBackup and Replication12.3.2 to < 12.3.2—

06 References