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Internet ExplorerApplication · Microsoft

CVE-1999-0967

HIGH · 10.0 CVSS v2.0 Published 1997-11-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Buffer overflow in the HTML library used by Internet Explorer, Outlook Express, and Windows Explorer via the res: local resource protocol.

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 confidence

Buffer overflow vulnerability in the HTML parsing library used by Internet Explorer, Outlook Express, and Windows Explorer. The flaw is triggered through the res: local resource protocol handler, which allows loading resources from the local system. This could allow remote code execution when processing maliciously crafted resource entries.

MitigationApply relevant Microsoft security patches for the affected legacy Microsoft products. Consider migrating away from affected legacy software as they are no longer supported. The res: protocol handler may be disabled via registry modifications if the products cannot be updated.

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
Internet ExplorerApplication
Affected:= 4.0
Outlook ExpressApplication
Affected:all versions
Windows ExplorerApplication
Affected:all versions

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
Complete
Integrity
Complete
Availability
Complete

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

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. Check Internet Explorer version
    Open Internet Explorer, then go to Help > About Internet Explorer. Alternatively, check the registry key HKLM\SOFTWARE\Microsoft\Internet Explorer\Version or look for iexplore.exe in Program Files and right-click > Properties > Details to see version info.
    Affected if The version is exactly 4.0 (all builds of IE 4.0 are affected)
  2. Check if Outlook Express is installed
    Look for msimn.exe in Program Files (x86)\Outlook Express or check Add/Remove Programs for Outlook Express. On older Windows, check Start menu for Outlook Express shortcut.
    Affected if Outlook Express is installed on the system (all versions are affected)
  3. Check if Windows Explorer is the legacy version
    Open Windows Explorer and note the interface style. On Windows 95/98/NT systems from this era, the shell is essentially Windows Explorer. Check system information for Windows version - older pre-NT systems running the legacy shell are affected.
    Affected if Running legacy Windows 95/98/NT with the older Windows Explorer shell (all versions are affected)
  4. Confirm the res: protocol handler exists
    Open Internet Explorer or Outlook Express and type res://path/to/resource in the address bar. If the browser attempts to load a local resource, the handler is present and active.
    Affected if The res: protocol is functional and can load local resources (required for the vulnerability to be triggerable)

If Internet Explorer version 4.0 is installed, or if Outlook Express or legacy Windows Explorer from the Windows 95/98/NT era are present with the res: protocol handler active, the system is vulnerable to this buffer overflow.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply relevant Microsoft security patches for the affected legacy Microsoft products. Consider migrating away from affected legacy software as they are no longer supported. The res: protocol handler may be disabled via registry modifications if the products cannot be updated.

Recommended fix Moderate confidence
  1. This is a 1999 vulnerability affecting obsolete software (Internet Explorer 4.0, Outlook Express, and Windows Explorer from the Windows 9x/early NT era).
  2. These products are no longer supported and cannot be patched through normal channels.
  3. For modern systems, ensure you are using current software: Microsoft Edge (not Internet Explorer) for browsing, and a modern email client instead of Outlook Express.
  4. If legacy systems require these applications, isolate them in highly restricted environments with no network access to the 'res:' protocol resources.
  5. Consider migrating away from any system still running these legacy applications as they pose significant security risks.
Caveat N/A - legacy unsupported software

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Internet Explorer Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-1999-0967 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
  • No spam, self-promotion, credentials, or personal data