CVE-2001-0136: Memory leak in ProFTPd 1.2.0rc2 allows remote attackers to cause a denial of service via a series of USER comm

This week

MEDIUM 5.0WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2001-0136 is a medium-severity flaw (CVSS 5.0) affecting proftpd, linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Memory leak in ProFTPd 1.2.0rc2 allows remote attackers to cause a denial of service via a series of USER commands, and possibly SIZE commands if the server has been improperly installed.

Why this priority

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

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	44.9% (top 1%)
CISA exploited list	No
Weakness	CWE-401
Published	2001-03-12
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: conectiva · debian · mandrakesoft · proftpd

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

Am I affected?

Timeline

2001-03-12 05:00 UTCPublished CVE record published
2026-06-16 21:53 UTCUpdated Record last modified

proftpd proftpd DOWNGRADE

Affected: 1.2.0 rc2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.0

1. Check installed version

apt-cache policy proftpd || rpm -q proftpd || proftpd --version

2. No fixed release: DOWNGRADE to a release before 1.2.0 (Debian / Ubuntu)

apt-cache madison proftpd sudo apt install proftpd=<VERSION_BEFORE_1.2.0> sudo apt-mark hold proftpd

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list proftpd sudo dnf downgrade proftpd-<VERSION_BEFORE_1.2.0> sudo dnf versionlock add proftpd

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.

conectiva linux MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 2.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mandrakesoft mandrake linux MITIGATE

Affected: 7.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.2

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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: ProFTPd 1.2 - 'SIZE' Remote Denial of Service
Exploit-DB: ProFTPd 1.2.0 pre10 - Remote Denial of Service
Exploit-DB: ProFTPd 1.2.0 rc2 - Memory Leakage

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-2001-0136?

proftpd: downgrade or apply the listed mitigation; linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2001-0136 being exploited?

CVE-2001-0136 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-2001-0136 affect?

CVE-2001-0136 affects proftpd, linux, debian linux. Severity is medium (CVSS 5.0). Memory leak in ProFTPd 1.2.0rc2 allows remote attackers to cause a denial of service via a series of USER commands, and possibly SIZE commands if the server has been improperly installed.

How urgent is CVE-2001-0136?

Priority 52/100. EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities · ProFTPD vulnerabilities

Related CVEs

CVE-2026-35025 HIGH 8.1 UPGRADE ProFTPD through 1.3.9b and 1.3.10rc2 contains an access control bypass vulnerability that allows authenticated
CVE-2026-53994 HIGH 7.5 UPGRADE ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user
CVE-2015-3306 CRITICAL 10.0 EXPLOITED MITIGATE MITIGATE ProFTPD Improper Access Control Vulnerability
CVE-2026-63090 HIGH 8.8 UPGRADE ProFTPD before 1.3.9c and 1.3.10rc3 contains a heap-based buffer overflow vulnerability in the mod_sftp module
CVE-2026-63091 MEDIUM 6.5 UPGRADE ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's

References

← Back to latest CVEs