CVE-2025-40806
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 Gridscale X Prepay (All versions < V4.2.1). The affected application is vulnerable to user enumeration due to distinguishable responses. This could allow an unauthenticated remote attacker to determine if a user is valid or not, enabling a brute force attack with valid users.
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 confidenceGridscale X Prepay versions prior to V4.2.1 contain a user enumeration vulnerability where the application returns distinguishable responses for valid versus invalid usernames. An unauthenticated remote attacker can send login requests with different usernames and analyze the response differences to determine which accounts exist in the system, facilitating targeted brute-force attacks.
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< 4.2.1CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Check Gridscale X Prepay installed versionLocate the version information for your Gridscale X Prepay installation through the product's built-in about panel, version command, or administrative interface. Consult product documentation for version location if not immediately visible.Affected if The installed version is any release prior to 4.2.1 (for example, 4.2.0, 4.1.x, or earlier)
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Identify the authentication endpointLocate the login or authentication endpoint in your Gridscale X Prepay installation. This is typically found at the application's login page or API entry point for user authentication.Affected if The endpoint accepts username input and processes authentication requests
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Test response for valid usernameSend an authentication request using a known-valid username (such as an administrator account or any existing user account) and capture the full HTTP response, including status code, response body, headers, and any error messages.Affected if The response contains any indication that the username exists, such as a password prompt, different error message, or different status code compared to invalid usernames
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Test response for invalid usernameSend an authentication request using a random or non-existent username and capture the full HTTP response. Compare all aspects (timing, status code, message content, headers) against the valid username response.Affected if The response differs from the valid username response in message text, error codes, timing, or any other distinguishable manner
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Verify response inconsistency across multiple attemptsRepeat the valid and invalid username tests multiple times to confirm the response differences are consistent and not due to random variation or rate limiting.Affected if Valid usernames consistently produce a different response than invalid usernames across multiple test cycles
You are affected if your Gridscale X Prepay version is below 4.2.1 and the login endpoint returns distinguishable responses for existing versus non-existing usernames.
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.
dbcve · scoped4.2.1
Implement uniform response messages for both valid and invalid usernames during authentication to prevent enumeration. Additionally, consider implementing rate limiting and account lockout mechanisms to further mitigate brute-force attempts.
V4.2.1
- Backup the current Gridscale X Prepay installation and database before upgrading
- Obtain the fixed version V4.2.1 from gridscale or Siemens customer portal
- Upgrade the Gridscale X Prepay installation to version 4.2.1 following the vendor's documented upgrade procedure
- After upgrade, verify that user enumeration is no longer possible by testing login/password reset flows with valid and invalid usernames to confirm responses are indistinguishable
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-40806 — 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-2025-40806 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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