IeApplication · Microsoft

CVE-2003-1328

HIGH · 7.5 CVSS v2.0 Published 2003-02-19
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
The showHelp() function in Microsoft Internet Explorer 5.01, 5.5, and 6.0 supports certain types of pluggable protocols that allow remote attackers to bypass the cross-domain security model and execute arbitrary code, aka "Improper Cross Domain Security Validation with ShowHelp functionality."

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

The showHelp() function in Internet Explorer 5.01, 5.5, and 6.0 fails to properly validate cross-domain security when handling pluggable protocols, allowing remote attackers to bypass same-origin restrictions and execute arbitrary code via malicious help content or protocol handlers.

MitigationReplace affected Internet Explorer versions with a supported, modern browser as these IE versions are obsolete and no longer receive security updates from Microsoft.

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
IeApplication
Affected:= 6.0
Internet ExplorerApplication
Affected:= 5.0.1= 5.5= 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 Internet Explorer installation status
    Check if Internet Explorer exists on the system by looking for iexplore.exe in typical locations such as C:\Program Files\Internet Explorer\iexplore.exe or C:\Program Files (x86)\Internet Explorer\iexplore.exe, or by checking the Windows registry key HKLM\SOFTWARE\Microsoft\Internet Explorer
    Affected if Internet Explorer is not found on the system, the system is not affected by this specific vulnerability
  2. Determine installed Internet Explorer version
    Open Internet Explorer, then navigate to Help > About Internet Explorer, or check the registry value at HKLM\SOFTWARE\Microsoft\Internet Explorer\Version
    Affected if The installed version is 5.01, 5.5, or 6.0 - these specific versions contain the vulnerable showHelp() function
  3. Confirm showHelp() function is present
    Examine the iexplore.exe binary or associated DLLs (such as shdocvw.dll or hhctrl.ocx) for the showHelp() implementation - this function handles .chm help file rendering and pluggable protocol handling
    Affected if The showHelp() function is present in the installed IE version, indicating the vulnerable code path exists
  4. Check for pluggable protocol handler exposure
    Verify that the system has .chm help files or custom protocol handlers registered that could be invoked through the showHelp() function - these are accessed via the ms-its, ms-itss, or mk:@ protocols
    Affected if Pluggable protocol handlers are registered and accessible to IE, which provides the attack surface for this vulnerability

A system is affected if Internet Explorer versions 5.01, 5.5, or 6.0 are installed and the showHelp() function with pluggable protocol support is present, allowing cross-domain security bypass.

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

Replace affected Internet Explorer versions with a supported, modern browser as these IE versions are obsolete and no longer receive security updates from Microsoft.

Fix this in Ie Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2003-1328 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2003-1328 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