---
title: "CVE-2015-3306: ProFTPD Improper Access Control Vulnerability"
url: https://erroneo.us/security/cve/CVE-2015-3306/
description: "CVE-2015-3306 (ProFTPD ProFTPD): Exploited in the wild (CISA KEV). The modcopy module in ProFTPD 1.3.5 allows remote attackers to read and write to…"
type: vulnerability-record
section: "Security Digest"
date_published: 2015-05-18
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2015-3306"
kev: true
cvss: 10
epss: 0.99497
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2015-3306: ProFTPD Improper Access Control Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run ProFTPD ProFTPD. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-08, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-10-11 ; treat that as the outer limit, not the target.
- EPSS 99.5% , percentile 99.9: FIRST’s model estimates a 99.5% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. ProFTPD mod_copy CVE-2015-3306: 2015 Bug Added to KEV — Nearly everyone fixed this a decade ago; the real job is finding any ProFTPD 1.3.5-era build with mod_copy still answering on port 21, usually inside old appliances, and replacing or removing it.

## What it is

The modcopy module in ProFTPD 1.3.5 allows remote attackers to read and write to arbitrary files via the site cpfr and site cpto commands.

## Affected products (CVE record)

- n/a n/a: see advisory

## Severity

- CISA-ADP CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2026-10-08; federal due date 2026-10-11. Known ransomware use: Unknown.
- CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 99.50% probability of exploitation activity in the next 30 days; percentile 99.9.

## Sources

- [DSA-3263](http://www.debian.org/security/2015/dsa-3263)
- [openSUSE-SU-2015:1031](http://lists.opensuse.org/opensuse-updates/2015-06/msg00020.html)
- [FEDORA-2015-7164](http://lists.fedoraproject.org/pipermail/package-announce/2015-May/157053.html)
- [FEDORA-2015-6401](http://lists.fedoraproject.org/pipermail/package-announce/2015-May/157054.html)
- [FEDORA-2015-7086](http://lists.fedoraproject.org/pipermail/package-announce/2015-May/157581.html)
- [Listed in CISA KEV notes (proftpd.org)](http://www.proftpd.org/)
- [Listed in CISA KEV notes (lists.debian.org)](https://lists.debian.org/debian-security-announce/2015/msg00154.html)
- [Listed in CISA KEV notes (lists.opensuse.org)](https://lists.opensuse.org/archives/list/updates@lists.opensuse.org/message/WE6YZRG5UVXMGQ7IVDRYBPIWV4M6UUGM/)
- [CVE.org record CVE-2015-3306](https://www.cve.org/CVERecord?id=CVE-2015-3306)
- [NVD entry CVE-2015-3306](https://nvd.nist.gov/vuln/detail/CVE-2015-3306)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-3306)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [rapid7.com](http://www.rapid7.com/db/modules/exploit/unix/ftp/proftpd_modcopy_exec)
- [36803](https://www.exploit-db.com/exploits/36803/)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/131555/ProFTPd-1.3.5-Remote-Command-Execution.html)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/131567/ProFTPd-CPFR-CPTO-Proof-Of-Concept.html)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/132218/ProFTPD-1.3.5-Mod_Copy-Command-Execution.html)
- [74238](http://www.securityfocus.com/bid/74238)
- [36742](https://www.exploit-db.com/exploits/36742/)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/131505/ProFTPd-1.3.5-File-Copy.html)
- [packetstormsecurity.com](http://packetstormsecurity.com/files/162777/ProFTPd-1.3.5-Remote-Command-Execution.html)

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Source page: https://erroneo.us/security/cve/CVE-2015-3306/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt