CVE-2009-2521

mediumpriority · attend · 59EPSS 0.823 · 100 %ileexploit · functionalEURUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

3 exploits · functional

Likely / severe?

82.3% (100th) EPSS

CVSS 5 · medium

Is it mine?

6 products

Check your exposure

Who says so?

3 sources

enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

Stack consumption vulnerability in the FTP Service in Microsoft Internet Information Services (IIS) 5.0 through 7.0 allows remote authenticated users to cause a denial of service (daemon crash) via a list (ls) -R command containing a wildcard that references a subdirectory, followed by a .. (dot dot), aka "IIS FTP Service DoS Vulnerability."

cvss

Technical severity, 0–10. One row per scoring source.

5.0

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.6–5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v2.02.6lowAV:N/AC:H/Au:N/C:N/I:N/A:Psecondary · FSTEC (BDU) RU

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:P/E:Hsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USprimaryCWE-399US

exploits (3)

Public proof-of-concept and weaponised exploit code.

EDB-9587Microsoft IIS 5.0/6.0 FTP Server - Stack Exhaustion Denial of Servicefunctional · exploit_db
auxiliary/dos/windows/ftp/iis_list_exhaustionMicrosoft IIS FTP Server LIST Stack Exhaustionfunctional · metasploit
EDB-17476Microsoft IIS 7.0 FTP Server - Stack Exhaustion Denial of Service (MS09-053) (Metasploit)PoC · exploit_db

affected products (6)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
ICP DAS Co. Ltd. XP-8741-Atom≤ XP-8741fstec_bduRU
Microsoft Corp Microsoft Internet Information Services≤ 7.0fstec_bduRU
Microsoft Corp Microsoft Internet Information Services≤ 6.0fstec_bduRU
Microsoft Corp Microsoft Internet Information Services≤ 5.0fstec_bduRU
microsoft internet information services5.0 → 7.0nvdUScpe:2.3:a:microsoft:internet_information_services:*:*:*:*:*:*:*:*

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2009-09-04modified 2026-06-16

related (9,612)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2026-28318US	—OT critical	43.7% (99th)	KEV	2026-06-04
SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate. Mitigation steps are provi…
CVE-2026-45498US	high7.5OT critical	63.1% (99th)	KEV	2026-05-20
Microsoft Defender Denial of Service Vulnerability
CVE-2023-44487US	high7.5OT critical	100.0% (100th)	KEV	2023-10-10
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through…
CVE-2023-38180US	—OT critical	14.1% (97th)	KEV	2023-08-08
.NET and Visual Studio Denial of Service Vulnerability
CVE-2021-44228US	critical10.0OT critical	100.0% (100th)	KEV	2021-12-10
Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect agai…

+9607 more

references (10)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan