CVE-2007-4040
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 · uneditedArgument injection vulnerability involving Microsoft Outlook and Outlook Express, when certain URIs are registered, allows remote attackers to conduct cross-browser scripting attacks and execute arbitrary commands via shell metacharacters in an unspecified URI, which are inserted into the command line when invoking the handling process, a similar issue to CVE-2007-3670.
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 · moderate confidenceThis is an argument injection vulnerability in Microsoft Outlook and Outlook Express where shell metacharacters in specially crafted URIs are inserted into the command line when the email client processes those URIs. Attackers can register malicious URI handlers to achieve cross-browser scripting and execute arbitrary commands on the affected system.
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 dataall versionsall versionsCVSS 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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Check if Microsoft Outlook is installedOpen Registry Editor and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Outlook or HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\Outlook. If the key exists, Outlook is installed.Affected if Microsoft Outlook is installed on the system
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Check if Outlook Express is installedOpen Registry Editor and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Outlook Express or check for the application file (msimn.exe) in Program Files.Affected if Microsoft Outlook Express is installed on the system
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Identify registered URI scheme handlersOpen Registry Editor and examine HKEY_CLASSES_ROOT\PROTOCOLS\Handler or HKEY_LOCAL_MACHINE\SOFTWARE\Classes\PROTOCOLS\Handler for URI scheme handlers registered on the system.Affected if Multiple URI handlers are registered that could be exploited by malicious schemes
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Check for custom URI handlers in OutlookExamine HKEY_CLASSES_ROOT\mailto\shell\open\command in Registry Editor to see how the mailto: protocol handler is configured.Affected if The mailto handler or other Outlook URI handlers are configured to process arguments
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Verify if Outlook processes HTML emailsIn Outlook, go to Tools > Options > Security tab or View > Message Format to check whether emails are rendered in HTML format.Affected if Outlook is set to display emails in HTML format, enabling URI processing
If either Microsoft Outlook or Outlook Express is installed, the system is potentially affected because the vulnerability exists in all versions of these products when they process URI schemes.
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 dataApply Microsoft security patches for this vulnerability, or unregister/disable problematic URI handlers to prevent malicious URI schemes from being processed by Outlook or Outlook Express.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2007-4040 — 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-2007-4040 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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