CVE-2011-5279

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

19.6% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2014-04-23 20:55 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:36 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 19.6% in the next 30 days (EPSS).
• Severity: 5.0 MEDIUM (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2014-04-23 20:55 UTC

Last modified

2026-06-16 23:36 UTC

Exploit probability

19.6% · EPSS, next 30 days

Record status

Modified

Affected

• Microsoft Internet Information Services 4.0
• Microsoft Internet Information Services 5.0

Attack profile CVSS 2.0 · 5.0

Attack vector

Network

Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2011-5279.md and follow it. Check whether this project is affected by CVE-2011-5279. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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