Unitrends Backup SoftwareApplication · Kaseya

CVE-2021-40385

HIGH · 8.8 CVSS v3.1 Published 2021-09-01
Fix available
A fix is available. Upgrade to 10.5.5-2 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

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 · unedited
An issue was discovered in the server software in Kaseya Unitrends Backup Software before 10.5.5-2. There is a privilege escalation from read-only user to admin.

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 · high confidence

Kaseya Unitrends Backup Software before version 10.5.5-2 contains a privilege escalation vulnerability allowing read-only users to elevate their privileges to administrator level. This is a server-side authorization bypass in the backup software's user management functionality.

MitigationUpgrade Kaseya Unitrends Backup Software to version 10.5.5-2 or later to remediate the vulnerability. Verify that read-only user accounts cannot access admin functions post-upgrade.

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
Unitrends Backup SoftwareApplication
Affected:< 10.5.5-2

CVSS 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Kaseya Unitrends Backup Software version
    Locate the version information for your Kaseya Unitrends Backup Software installation through the software's about panel, help menu, or system information interface. This is typically found in the administration console under System or Settings.
    Affected if The installed version is any release before 10.5.5-2 (for example, 10.5.5-1, 10.5.4, 10.x.x, or earlier)
  2. Identify read-only user accounts
    Access the user management section of the Kaseya Unitrends Backup Software administration console and review the list of defined user accounts. Note which accounts are assigned read-only or limited user roles.
    Affected if There are one or more user accounts configured with read-only or limited access permissions in the system
  3. Verify authorization behavior for read-only users
    Log in to the backup software using a read-only user account. Attempt to access administrative functions such as user management, system configuration, backup job creation/modification, or other privileged operations. Document which admin functions are accessible.
    Affected if A read-only user account can successfully access, modify, or perform administrative functions that should be restricted to administrator-level users
  4. Inspect user role permissions configuration
    In the administration console, navigate to the user roles or permissions configuration area. Review the permission mappings for read-only roles to determine if authorization checks are properly enforced for privileged operations.
    Affected if The read-only role configuration shows elevated permissions or the authorization checks for admin functions appear to be bypassed

Your environment is affected if the installed Kaseya Unitrends Backup Software version is below 10.5.5-2 AND read-only user accounts can successfully access or perform administrator-level functions in the software.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 10.5.5-2 or later
Fixed in 10.5.5-2
Interim mitigation

Upgrade Kaseya Unitrends Backup Software to version 10.5.5-2 or later to remediate the vulnerability. Verify that read-only user accounts cannot access admin functions post-upgrade.

Recommended fix High confidence

10.5.5-2 or later

  1. Upgrade Unitrends Backup Software to version 10.5.5-2 or later to remediate the privilege escalation vulnerability

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Unitrends Backup Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,300
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,680.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-40385 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40385 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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