CVE-2021-40335
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 exists in the HTTP web interface where the web interface does not sufficiently verify if a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. This cause a Cross Site Request Forgery (CSRF), which if exploited could lead an attacker to gain unauthorized access to the web application and perform an unwanted operation on it without the knowledge of the legitimate user. An attacker, who successfully makes an MSM user who has already established a session to MSM web interface clicks a forged link to the MSM web interface, e.g., link is sent per E-Mail, could perform harmful command on MSM through its web server interface. This issue affects: Hitachi Energy MSM V2.2 and prior versions.
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 confidenceHitachi Energy MSM V2.2 and prior versions contain a Cross-Site Request Forgery (CSRF) vulnerability in the HTTP web interface. The application lacks proper verification (anti-CSRF tokens or request validation) to confirm that requests originate from the legitimate authenticated user, allowing attackers to trick authenticated users into performing unintended operations via malicious links.
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<= 2.2.0CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Confirm MSM web interface is accessibleAccess the device's IP address via HTTP/HTTPS in a browser to verify the Hitachi Energy Modular Switchgear Monitoring web interface is reachableAffected if The MSM web interface is exposed and accessible on the network
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Identify firmware versionLog into the MSM web interface and navigate to System Information, About, or Settings page to view the firmware version. Alternatively, check the HTTP response headers or error pages for version informationAffected if The installed firmware version is 2.2.0 or lower
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Inspect HTML forms for anti-CSRF tokensView the page source (right-click > View Page Source) of state-changing forms (configuration, control actions, user management) and search for hidden input fields containing names like 'csrf', 'token', 'nonce', or 'xsrf'. Check if each form submission includes a unique token parameterAffected if Forms lack hidden anti-CSRF token fields or the tokens are missing from form submissions
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Verify cookie SameSite attributesOpen browser developer tools (F12), go to Application/Storage tab, examine cookies set by the MSM application, and inspect the SameSite and Secure attributes for session cookiesAffected if Session cookies lack SameSite=Strict or SameSite=Lax attributes
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Test referrer/Origin header validationSubmit a form request with a mismatched or missing Referer/Origin header (using a tool like Burp Suite or curl) to determine if the application rejects the requestAffected if The application accepts requests without validating Referer or Origin headers
The environment is affected if the MSM firmware version is 2.2.0 or lower AND the web interface lacks anti-CSRF tokens in forms, proper cookie attributes, and referrer/Origin validation.
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 anti-CSRF tokens or unique request identifiers for all state-changing operations (forms, API endpoints), enable SameSite cookie attributes, and add referrer/Origin header validation. User sessions should also include secondary confirmation for sensitive operations.
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-40335 — 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-2021-40335 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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- 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
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