# CVE-1999-0191: Microsoft IIS file overwrite in newdsn.exe CGI script

Source: https://junglewise.ai/threats/cve-1999-0191-microsoft-iis-file-overwrite-in-newdsn-exe-cgi-script  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1997-09-01. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0191 · Severity: medium · CVSS 6.4 · Published 1997-09-01

A vulnerability in a legacy Microsoft IIS component allows remote users to overwrite files on the web server. This component is part of the system used to manage web-based data sources. An attacker could exploit this to corrupt system files or modify website content, potentially leading to a loss of data integrity or unauthorized site changes.

Technologies: [Microsoft Internet Information Services](https://junglewise.ai/threats/technologies/internet-information-services). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-1999-0191 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0191 being exploited in the wild.

**How severe is CVE-1999-0191?** Medium severity, with a CVSS score of 6.4, published 1 September 1997.

**Which products and versions are affected?** Microsoft Internet Information Services (IIS).

**Is there a fix for CVE-1999-0191?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-1999-0191 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-1999-0191?** Check whether you run Microsoft Internet Information Server or Microsoft Internet Information Services. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the newdsn.exe CGI script, which is part of the Microsoft Internet Information Services (IIS) suite. The script fails to properly validate or restrict file operations, allowing a remote, unauthenticated attacker to overwrite arbitrary files on the host system via a network request. This is a file manipulation vulnerability that can lead to unauthorized modification of data or system configuration. The attack is reachable over the network without requiring user interaction or prior authentication.

## Affected products

- Microsoft Internet Information Services (IIS)

## Timeline

- 1997-09-01: disclosed

## References

- [http://www.osvdb.org/275](http://www.osvdb.org/275)

## Related threats

- [Windows Internet Information Services denial of service](https://junglewise.ai/threats/cve-2026-119909-uncontrolled-resource-consumption-in-windows-internet)
- [Microsoft Windows Web Servers access bypass via long filenames](https://junglewise.ai/threats/cve-1999-0012-microsoft-windows-web-servers-access-bypass-via-long-filenames)
- [Microsoft IIS denial of service via long URLs](https://junglewise.ai/threats/cve-1999-0281-microsoft-iis-denial-of-service-via-long-urls)
- [Microsoft IIS source code disclosure via URL encoding](https://junglewise.ai/threats/cve-1999-0253-microsoft-iis-source-code-disclosure-via-url-encoding)
- [Microsoft IIS arbitrary command execution via .bat and .cmd files](https://junglewise.ai/threats/cve-1999-0233-microsoft-iis-arbitrary-command-execution-via-bat-and-cmd-files)