CVE-2026-21671
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability allowing an authenticated user with the Backup Administrator role to perform remote code execution (RCE) in high availability (HA) deployments of Veeam Backup & Replication.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA vulnerability in Veeam Backup & Replication's high availability deployments allows an authenticated user with Backup Administrator privileges to execute arbitrary code remotely. The CVSS 9.1 score reflects the critical severity of network-exploitable RCE combined with low attack complexity, requiring only valid Backup Administrator credentials.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 13.0.0.496, <= 13.0.1.1071CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify Veeam Backup & Replication is installedOpen Windows Programs and Features or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Where-Object {$_.DisplayName -like "*Veeam*"}' to list installed Veeam productsAffected if Veeam Backup & Replication appears in the installed programs list
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Check installed Veeam Backup & Replication versionOpen Veeam Backup & Replication console and view the About page, or check the version in registry at HKLM:\SOFTWARE\Veeam\Veeam Backup & Replication\Version or via PowerShell: (Get-ItemProperty 'HKLM:\SOFTWARE\Veeam\Veeam Backup & Replication').VersionAffected if The version number falls within the range 13.0.0.496 through 13.0.1.1071 (inclusive)
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Determine if High Availability is configuredIn Veeam Backup & Replication console, navigate to the High Availability section or run Get-VBRHighAvailabilityCluster in Veeam PowerShell module to check for HA cluster configurationAffected if High Availability is enabled or an HA cluster is configured in the environment
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Identify Backup Administrator accountsIn Veeam Backup & Replication console, go to Users and Roles section to list accounts with Backup Administrator privileges, or run Get-VBRUser in Veeam PowerShellAffected if Any user account holds Backup Administrator role privileges
Environment is affected if Veeam Backup & Replication version is between 13.0.0.496 and 13.0.1.1071 AND High Availability is deployed AND at least one user has Backup Administrator privileges.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor-supplied patches when available; restrict Backup Administrator role assignments to trusted personnel only and audit existing role assignments in HA environments.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-21671 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-21671 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data