Threat Intelligence / CVE / CVE-2026-21667

CVE-2026-21667 — Veeam Backup & Replication

CVSS v3.1 9.9 (CRITICAL) · EPSS 0.3% (higher than 53.5% of all scored CVEs) · Priority 7.1/10 · Published 2026-03-12

As of 2026-03-31, CVE-2026-21667 is a CRITICAL-severity vulnerability in Veeam Backup & Replication, CVSS v3.1 9.9, EPSS 0.3% (53.5th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-21667, most recently “Veeam Backup & Replication 8 Critical Vulnerabilities — Domain User to Backup Server RCE (CVE-2026-21666, CVE-2026-21667, CVE-2026-21669, CVE-2026-21708)”.

Last updated: 2026-03-31

What is CVE-2026-21667?

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

The record classifies CVE-2026-21667 under weakness class CWE-284. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 187 days ago.

Severity and exploitation probability

CVSS v3.1 base score
9.9 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS (FIRST)
0.3% probability of exploitation in the next 30 days, higher than 53.5% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
7.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-03-12, last modified 2026-03-31

Is CVE-2026-21667 being exploited?

It currently carries a trending score of 18 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-21667

The record marks a vendor fix as available for CVE-2026-21667. Vendor advisory: https://www.veeam.com/kb4830. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-21667

1 tracked threat in the Threadlinqs corpus references CVE-2026-21667, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Seeded from threadlinqs-intel and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-21667 are available via the Threadlinqs MCP server (Purple tier). View plans →

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