CVE-1999-0725
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 · uneditedWhen IIS is run with a default language of Chinese, Korean, or Japanese, it allows a remote attacker to view the source code of certain files, a.k.a. "Double Byte Code Page".
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 confidenceIIS web servers configured with default language settings for Chinese, Korean, or Japanese (Double Byte Character Set code pages) fail to properly parse file requests, allowing remote attackers to obtain source code of server-side scripts instead of their executed output.
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= 3.0= 4.0CVSS 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
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- None
- Availability
- None
AV:N/AC:M/Au:N/C:C/I:N/A:N
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 IIS version is 3.0 or 4.0Check the IIS version via the registry key HKLM\SOFTWARE\Microsoft\InetStp\VersionString, or run 'iisreset /status' or check inetmgr snap-inAffected if Installed version is 3.0 or 4.0
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Locate the IIS default language settingOpen the Windows registry and navigate to HKLM\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters\DefaultLangIDAffected if This registry value exists and is readable
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Identify the language code page configurationRead the DefaultLangID value; values for CJK locales include 1042 (Korean), 2052 (Simplified Chinese), 1028 (Traditional Chinese), 1041 (Japanese)Affected if The DefaultLangID value is set to a CJK code page (1041, 1042, 1028, or 2052) or the server default language is configured to Chinese, Korean, or Japanese in IIS Manager under Web Site Properties -> Documents -> Enable default document
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Verify script mapping behaviorRequest a known .asp file via HTTP and inspect whether the raw source code is returned instead of executed outputAffected if The server returns unexecuted ASP source code instead of processing the script
You are affected if running IIS 3.0 or 4.0 with the default language/code page configured to a Chinese, Korean, or Japanese locale, allowing script source disclosure.
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 dataConfigure IIS default language to a non-CJK locale or apply the historical Microsoft patch (MS99-019) for this vulnerability.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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 locallyCheck whether your project pulls in CVE-1999-0725 — 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-1999-0725 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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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.
- 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