CVE-2021-40336
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 validate data in an HTTP header. This causes a possible HTTP response splitting, which if exploited could lead an attacker to channel down harmful code into the user’s web browser, such as to steal the session cookies. Thus, 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., the link is sent per E-Mail, could trick the user into downloading malicious software onto his computer. 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 an HTTP response splitting (CRLF injection) vulnerability in the web interface. The application fails to validate data in HTTP headers, allowing attackers to inject malicious headers via specially crafted links. When a user with an active session clicks a forged link, attackers can steal session cookies or trick users into downloading malicious software.
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 Hitachi Energy MSM is deployedIdentify if the Hitachi Energy Modular Switchgear Monitoring product is installed in your environment. Check network scans, asset inventories, or consult with IT infrastructure teams for systems running this software.Affected if The system has Hitachi Energy MSM installed
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Check installed firmware versionAccess the MSM device console or admin interface and locate the firmware version information. Compare this version number against the affected range of <= 2.2.0.Affected if The installed firmware version is 2.2.0 or prior
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Verify web interface is enabledDetermine if the MSM web interface is accessible and active. Check network configurations, firewall rules, or the device administration panel to confirm the HTTP web service is running.Affected if The web interface is enabled and accessible over HTTP/HTTPS
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Inspect HTTP header handlingIf you have authorized access, test the web interface by submitting requests with special characters in input fields that might be reflected in HTTP headers. Monitor responses for any indication that carriage return (\r) and line feed (\n) characters are not being filtered or rejected.Affected if The application does not sanitize or reject CRLF characters in header inputs
You are affected if your installed Hitachi Energy MSM firmware version is 2.2.0 or prior AND the web interface is enabled and accessible, as the CRLF injection vulnerability exists in the unpatched web interface.
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 validation and sanitization of all HTTP header data to prevent CRLF injection. Header values should be checked for carriage return (\r) and line feed (\n) characters and rejected or sanitized before being used in HTTP responses.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-40336 — 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-2021-40336 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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