CVE-2026-42167: mod_sql in ProFTPD before 1.3.9a allows remote attackers to execute arbitrary code via a username, in scenario

Q: How do I fix CVE-2026-42167?

proftpd: upgrade to newer than 1.3.9b. Exact commands for each OS are on this page.

Q: Is CVE-2026-42167 being exploited?

CVE-2026-42167 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-42167 affect?

CVE-2026-42167 affects proftpd. Severity is high (CVSS 8.1). mod_sql in ProFTPD before 1.3.9a allows remote attackers to execute arbitrary code via a username, in scenarios where there is logging of USER requests with an expansion such as %U, and the SQL backend allows commands (e.g., COPY TO PROGRAM

Q: How urgent is CVE-2026-42167?

Priority 62/100. High severity; EPSS top 6%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 8.1REMOTEUPGRADE

CVE-2026-42167 is a high-severity flaw (CVSS 8.1) affecting proftpd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

mod_sql in ProFTPD before 1.3.9a allows remote attackers to execute arbitrary code via a username, in scenarios where there is logging of USER requests with an expansion such as %U, and the SQL backend allows commands (e.g., COPY TO PROGRAM).

Why this priority

High severity
EPSS top 6%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	7.4% (top 6%)
CISA exploited list	No
Weakness	CWE-89
Published	2026-04-28
Last modified	2026-07-24

Publisher (CNA): MITRE · Vendor: proftpd

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-28 23:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

proftpd proftpd UPGRADE

Affected: <= 1.3.9b

Fixed in: newer than 1.3.9b

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.3.9b (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade proftpd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade proftpd

Note

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

Exact fixes by distribution

Fedora 46 · python-python-ulid · FIXED · 4.1.0-2.fc46 · FEDORA-2026-3652e4825b · source

sudo dnf upgrade --advisory=FEDORA-2026-3652e4825b

Fedora ELN · gmp · FIXED · 6.3.0-7.eln159 · FEDORA-2026-1139089b36 · source

sudo dnf upgrade --advisory=FEDORA-2026-1139089b36

Debian 12 · proftpd-dfsg · FIXED · 1.3.8+dfsg-4+deb12u5

sudo apt update && sudo apt install --only-upgrade proftpd-dfsg dpkg --compare-versions "$(dpkg-query -W -f='${Version}' proftpd-dfsg)" ge "1.3.8+dfsg-4+deb12u5" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · proftpd-dfsg · FIXED · 1.3.8.c+dfsg-4+deb13u2

sudo apt update && sudo apt install --only-upgrade proftpd-dfsg dpkg --compare-versions "$(dpkg-query -W -f='${Version}' proftpd-dfsg)" ge "1.3.8.c+dfsg-4+deb13u2" && echo PATCHED || echo STILL-VULNERABLE

Alpine 3.22 · proftpd · FIXED · proftpd-1.3.9a-r0

apk add --upgrade proftpd apk info -v proftpd

Alpine 3.23 · proftpd · FIXED · proftpd-1.3.9a-r0

apk add --upgrade proftpd apk info -v proftpd

Alpine 3.24 · proftpd · FIXED · proftpd-1.3.9a-r0

apk add --upgrade proftpd apk info -v proftpd

Public exploits and detection

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

GitHub PoC: ZeroPathAI/proftpd-CVE-2026-42167-poc (30 stars)
GitHub PoC: dinosn/proftpd-CVE-2026-42167-analysis (3 stars)
Write-up: zeropath.com/blog/proftpd-cve-2026-42167-auth-bypass-privesc-rce
Exploit-DB: CVE-2026-42167 - ProFTPD mod_sql post-authentication SQLi - RCE
Nuclei scan template: ProFTPD mod_sql - Preauth User Backdoor

Advisories and coverage

Research and news

Exploit-DB Latest: [remote] CVE-2026-42167 - ProFTPD mod_sql post-authentication SQLi - RCE 2026-08-25

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-2026-42167?

proftpd: upgrade to newer than 1.3.9b. Exact commands for each OS are on this page.

Is CVE-2026-42167 being exploited?

CVE-2026-42167 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-2026-42167 affect?

CVE-2026-42167 affects proftpd. Severity is high (CVSS 8.1). mod_sql in ProFTPD before 1.3.9a allows remote attackers to execute arbitrary code via a username, in scenarios where there is logging of USER requests with an expansion such as %U, and the SQL backend allows commands (e.g., COPY TO PROGRAM

How urgent is CVE-2026-42167?

Priority 62/100. High severity; EPSS top 6%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

ProFTPD vulnerabilities

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References

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