Outlook ExpressApplication · Microsoft

CVE-2001-0999

HIGH · 7.5 CVSS v2.0 Published 2001-09-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
Outlook Express 6.00 allows remote attackers to execute arbitrary script by embedding SCRIPT tags in a message whose MIME content type is text/plain, contrary to the expected behavior that text/plain messages will not run script.

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 confidence

Outlook Express 6.00 improperly processes SCRIPT tags embedded in MIME messages despite the content-type being text/plain. The application incorrectly executes embedded JavaScript code that should be rendered as plain text, allowing remote attackers to run arbitrary scripts on the victim's system through specially crafted email messages.

MitigationApply the relevant Microsoft security update for Outlook Express or upgrade to a supported email client. This is a 2001 vulnerability affecting legacy 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
Outlook ExpressApplication
Affected:= 6.0

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/A:P

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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify Outlook Express 6.0 is installed
    Check the installed programs list in Windows Control Panel, or right-click the Outlook Express icon and select Properties to view version information
    Affected if Microsoft Outlook Express version 6.0 is present on the system
  2. Confirm the exact Outlook Express version
    Open Outlook Express, go to Help > About Microsoft Outlook Express and note the precise version number displayed
    Affected if The version displays as exactly 6.0 without any subsequent service pack or patch version indicators
  3. Check if Outlook Express processes email
    Verify that Outlook Express is configured as the default email client or is actively used to receive and display MIME-encoded messages
    Affected if Outlook Express 6.0 is configured to receive or display email messages containing MIME content
  4. Verify email HTML script handling
    Send or receive a test MIME message containing a SCRIPT tag in text/plain content-type and observe whether the script executes or displays as plain text
    Affected if Embedded SCRIPT tags in text/plain MIME messages are executed rather than displayed as text (confirming the vulnerable parsing behavior)

The environment is affected if Microsoft Outlook Express version 6.0 is installed and processes MIME-encoded email messages, as the vulnerability exists in the core message parsing regardless of configuration settings.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Microsoft security update for Outlook Express or upgrade to a supported email client. This is a 2001 vulnerability affecting legacy software.

Fix this in Outlook Express Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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Scan for this in your stack

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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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2001-0999 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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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