CVE-2025-40804
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 has been identified in SIMATIC Virtualization as a Service (SIVaaS) (All versions). The affected application exposes a network share without any authentication. This could allow an attacker to access or alter sensitive data without proper authorization.
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 confidenceSIMATIC Virtualization as a Service (SIVaaS) exposes a network share without any authentication mechanism, allowing unauthenticated remote attackers to access and potentially modify sensitive data. This represents a critical authentication bypass vulnerability given the CVSS score of 9.1.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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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Identify if SIMATIC Virtualization as a Service (SIVaaS) is installedCheck system inventory or running services for SIMATIC Virtualization as a Service or SIVaaS components. On Windows, review installed programs or running services. On Linux, check for SIVaaS-related processes or containers.Affected if SIVaaS is present in the environment
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Identify network shares exposed by the SIVaaS systemOn the SIVaaS host, use 'net share' (Windows) or 'smbclient -L //localhost' (Linux) to enumerate all network shares. Also check for NFS exports using 'showmount -e localhost'. Review documentation or configuration for shares managed by SIVaaS.Affected if SIVaaS is exposing any network share (SMB/CIFS or NFS)
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Test network share access without authenticationAttempt to access the identified shares from a different machine using 'smbclient //<SIVaaS-IP>/<share> -N' (no password) or 'mount -t cifs //<SIVaaS-IP>/<share> /mnt -o guest' for SMB, or 'mount -t nfs <SIVaaS-IP>:/<share> /mnt' for NFS without credentials.Affected if The share can be mounted or listed without providing any username or password
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Verify the share is not protected by external authenticationCheck if the share requires authentication by examining SMB/CIFS configuration files (smb.conf) or NFS export options (/etc/exports) on the SIVaaS system. Look for 'guest ok', 'public', or 'no_root_squash' settings.Affected if The share configuration allows unauthenticated or guest access
If SIVaaS is running and exposes a network share that is accessible without any authentication credentials, the environment is affected by this vulnerability.
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 dataImplement proper authentication and authorization controls on the exposed network share, or if the share is not required for operation, disable it entirely. Network segmentation and access control lists should be reviewed as compensating controls until the vulnerability is remediated.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-40804 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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- Version or environment caveats, and links to real fixes
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