CVE-2009-4445

6.0 MEDIUM 13% exploit odds No fix listed Other Web app

What it is

Microsoft Internet Information Services (IIS), when used in conjunction with unspecified third-party upload applications, allows remote attackers to create empty files with arbitrary extensions via a filename containing an initial extension followed by a : (colon) and a safe extension, as demonstrated by an upload of a .asp:.jpg file that results in creation of an empty .asp file, related to support for the NTFS Alternate Data Streams (ADS) filename syntax. NOTE: it could be argued that this is a vulnerability in the third-party product, not IIS, because the third-party product should be applying its extension restrictions to the portion of the filename before the colon.

At a glance

Exploitability: Can be exploited over the network with a login. Limited direct impact.
Exploit odds: 12.8% 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

2009-12-29 21:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-16 23:13 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 12.8% in the next 30 days (EPSS).
Severity: 6.0 MEDIUM (CVSS).
Fix: none linked yet, which raises it.

Details

Published: 2009-12-29 21:00 UTC
Last modified: 2026-06-16 23:13 UTC
Exploit probability: 12.8% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Modified

Affected

Microsoft Internet Information Services ≤ 6.0

Attack profile CVSS 2.0 · 6.0

Attack vector: Network
Complexity: Medium
Authentication: Single
Confidentiality: Partial
Integrity: Partial
Availability: Partial

Raw vector

AV:N/AC:M/Au:S/C:P/I:P/A:P

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-2009-4445.md and follow it. Check whether this project is affected by CVE-2009-4445. 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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References

NVD record · CVE.org record