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CloudstackApplication · Apache

CVE-2026-25077

HIGH · 8.8 CVSS v3.1 Published 2026-05-08
Fix available
A fix is available. Upgrade to 4.20.3.0 / 4.22.0.1 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
Account users are allowed by default to register templates to be downloaded directly to the primary storage for deploying instances using the KVM hypervisor. Due to missing file name sanitization, an attacker can register malicious templates to execute arbitrary code on the KVM hosts. This can result in the compromise of resource integrity and confidentiality, data loss, denial of service, and availability of the KVM-based infrastructure managed by CloudStack. Users are recommended to upgrade to Apache CloudStack versions 4.20.3.0 or 4.22.0.1, or later, which fixes this issue.

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

A missing file name sanitization vulnerability in Apache CloudStack allows authenticated account users to register malicious templates that execute arbitrary code on KVM hypervisor hosts, compromising the entire KVM-based cloud infrastructure.

MitigationUpgrade Apache CloudStack to version 4.20.3.0, 4.22.0.1, or later to patch the file name sanitization issue.

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
CloudstackApplication
Affected:>= 4.11.0.0, < 4.20.3.0>= 4.21.0.0, < 4.22.0.1

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. Identify Apache CloudStack version
    Check the CloudStack management server version through the UI under 'About CloudStack' or by querying the database: SELECT version FROM cloud.version WHERE name='cloudstack' ORDER BY id DESC LIMIT 1;
    Affected if The installed version falls within < 4.20.3.0 OR >= 4.21.0.0 AND < 4.22.0.1
  2. Confirm KVM hypervisor is in use
    Check the hypervisor type configured for zones and hosts in CloudStack: SELECT hypervisor_type FROM cloud.hosts WHERE type='Routing' AND removed IS NULL GROUP BY hypervisor_type;
    Affected if Any host shows 'KVM' as the hypervisor type, indicating KVM-based infrastructure is present
  3. Verify template registration is accessible
    Confirm the template registration API or UI feature is available to authenticated user accounts: Check if users have access to the 'Register Template' capability via account permissions or API endpoint.
    Affected if Authenticated user accounts can access template registration functionality

The environment is affected if CloudStack version is between 4.11.0.0 and 4.20.3.0 (exclusive), or between 4.21.0.0 and 4.22.0.1 (exclusive), AND KVM hypervisor is used, AND template registration is accessible to authenticated users.

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 4.20.3.0 / 4.22.0.1 or later
Fixed in 4.20.3.04.22.0.1
Interim mitigation

Upgrade Apache CloudStack to version 4.20.3.0, 4.22.0.1, or later to patch the file name sanitization issue.

Recommended fix High confidence

Apache CloudStack 4.20.3.0 or 4.22.0.1 (or later stable release)

  1. 1. Back up your current Apache CloudStack database and configuration files.
  2. 2. Stop all CloudStack services (management server, KVM agents).
  3. 3. Upgrade the CloudStack management server to version 4.20.3.0 or 4.22.0.1 (or later) using your distribution's package manager or build from source.
  4. 4. Run any required database migration scripts provided in the upgrade (e.g., 'cloudstack-sysvm' or similar upgrade tools).
  5. 5. Restart the CloudStack management server services.
  6. 6. Upgrade KVM agent packages on all KVM hypervisor hosts to match the new CloudStack version.
  7. 7. Verify the upgrade by logging into the CloudStack UI and confirming the version number.
  8. 8. Test template registration functionality to confirm the fix is applied.
Caveat Review release notes for any configuration or API changes between your current version and the target upgrade version before proceeding.

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

Fix this in Cloudstack Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-25077 in production — separate from our analysis above.

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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