CVE-2009-3023: Buffer overflow in the FTP Service in Microsoft Internet Information Services (IIS) 5.0 through 6.0 allows rem

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HIGH 9.0WATCHLISTUPGRADE

CVE-2009-3023 is a high-severity flaw (CVSS 9.0) affecting internet information server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in the FTP Service in Microsoft Internet Information Services (IIS) 5.0 through 6.0 allows remote authenticated users to execute arbitrary code via a crafted NLST (NAME LIST) command that uses wildcards, leading to memory corruption, aka "IIS FTP Service RCE and DoS Vulnerability."

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.0 (High)
EPSS exploit chance	90.9% (top 1%)
CISA exploited list	No
Weakness	CWE-120
Published	2009-08-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: microsoft

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-08-31 20:30 UTCPublished CVE record published
2026-06-16 23:10 UTCUpdated Record last modified

microsoft internet information server UPGRADE

Affected: >= 5.0 and <= 6.0

Fixed in: newer than 6.0

Safe to downgrade to: a release before 5.0

1. Check installed version

apt-cache policy internet-information-server || rpm -q internet-information-server || internet-information-server --version

2. UPGRADE to newer than 6.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade internet-information-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade internet-information-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.0 (Debian / Ubuntu)

apt-cache madison internet-information-server sudo apt install internet-information-server=<VERSION_BEFORE_5.0> sudo apt-mark hold internet-information-server

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list internet-information-server sudo dnf downgrade internet-information-server-<VERSION_BEFORE_5.0> sudo dnf versionlock add internet-information-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Microsoft IIS 5.0 FTP Server (Windows 2000 SP4) - Remote Stack Overflow
Exploit-DB: Microsoft IIS 5.0/6.0 FTP Server (Windows 2000) - Remote Stack Overflow
Exploit-DB: Microsoft IIS FTP Server - NLST Response Overflow (MS09-053) (Metasploit)
Metasploit: MS09-053 Microsoft IIS FTP Server NLST Response Overflow

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2009-3023?

internet information server: upgrade to newer than 6.0. Exact commands for each OS are on this page.

Is CVE-2009-3023 being exploited?

CVE-2009-3023 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2009-3023 affect?

CVE-2009-3023 affects internet information server. Severity is high (CVSS 9.0). Buffer overflow in the FTP Service in Microsoft Internet Information Services (IIS) 5.0 through 6.0 allows remote authenticated users to execute arbitrary code via a crafted NLST (NAME LIST) command that uses wildcards, leading to memory co

How urgent is CVE-2009-3023?

Priority 66/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist

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References

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