CVE-2017-6465

Public exploit available. Not confirmed exploited in the wild yet. No fix published yet.

CVSS 3.09.8Critical EPSS percentile99th50% chance in 30 days CISA KEVNot listedNo confirmed exploitation
Public exploit: 2 sources FixNone yetNo fix or workaround published

Published 2017-03-10Updated 2026-05-13Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build or workaround is published yet. Limit exposure and watch for a patch.

Steps

Written by AI from the record

Check whether you use FTPShell Client and confirm you are on version 6.53.
If you are using FTPShell Client 6.53, stop using it for any external FTP/FTPS connections immediately.
Replace it with a different client or upgrade to a fixed version—if your vendor cannot provide a fixed version, plan an urgent replacement.
Confirm there is no compensating control you can apply at the network level to block exposure from untrusted servers (only allow approved destinations).

May need vendor or contractor work

Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

Remote Code Execution was discovered in FTPShell Client 6.53. By default, the client sends a PWD command to the FTP server it is connecting to; however, it doesn't check the response's length, leading to a buffer overflow situation.

In plain language

Written by AI from the record

CVE-2017-6465 is a critical remote code execution flaw in FTPShell Client 6.53 that can let an attacker take over the machine when the client connects—there’s no known fix, so you should treat this as urgent if you use it.

CVE-2017-6465 describes a buffer overflow (CWE-119) in FTPShell Client 6.53 triggered by improper handling of the FTP server’s response to the default PWD command, with a public exploit available; no patch is known.

If you're affected

Full system takeover
Malware installation
Business interruption
Data theft risk

What is it

This vulnerability is like a software “handshake” bug during file-transfer connections. When the client asks the server a simple question (PWD) and the server replies in a specially crafted way, the client can crash or be tricked into running attacker code. In practical terms, it can lead to a complete takeover of the computer running the client.

Who is affected

This matters if your business uses FTPShell Client 6.53 to connect to FTP/FTPS servers, especially anything outside your tightly controlled internal network. Because the flaw is triggered during the connection sequence, it becomes a risk when you connect to a malicious or compromised server you don’t fully trust. End-to-end risk depends on whether an attacker can reach the connection path to the server you’re connecting to.

How urgent is it

This is RED because remote code execution has a public exploit available and the flaw is actively being discussed more widely. With no known patch information available, you should treat this as an immediate removal/replacement priority for any systems using FTPShell Client 6.53.

What to do — in detail

Confirm exposure
- Find every installed instance of FTPShell Client in your business environment.
- Verify the exact version you’re running; this finding specifically targets FTPShell Client 6.53.
Determine whether you’re reachable from untrusted endpoints
- List the FTP/FTPS destinations the client connects to.
- Ensure only approved, trusted servers are reachable from the client systems (restrict outbound connections where possible).
- If you connect to third-party servers, treat them as higher risk unless you have strong assurance they are legitimate and uncompromised.
Immediate mitigation (if you are using FTPShell Client 6.53)
- Stop using FTPShell Client 6.53 for external transfers right away.
- Remove the application from any systems that can connect to untrusted networks.
- Replace it with an alternative file-transfer client that is not known to have this issue.
Patch status / upgrade path
- Based on the available findings, no fix/patch information is available for this CVE.
- If your vendor provides an emergency update, apply it; otherwise, use replacement/upgrade by switching clients or changing tooling.
Temporary workaround while replacement is in progress
- Restrict outbound FTP/FTPS traffic from the affected machines to only the exact approved IPs/hostnames you control or have verified.
- If your workflow allows it, queue transfers through a more controlled gateway system that you harden and monitor (so only that gateway can reach external servers).
Validate after changes
- Re-check that no machines still run FTPShell Client 6.53.
- Confirm transfer jobs are succeeding after the switch.
What to monitor
- Look for signs of compromise on any host that used the vulnerable client (unexpected new processes, suspicious startup items, unusual outbound connections). If you see indicators, treat it as a suspected intrusion and escalate to incident response immediately.

Technical context

Severity is critical (CVSS 9.8 provided). The weakness is a buffer overflow (CWE-119) reachable via the client’s default behavior: it sends a PWD command when connecting, but does not properly validate the length of the server response; a crafted response can trigger memory corruption and enable remote code execution. Exploit maturity: a public exploit is available (2 known). KEV is not listed, so this is not confirmed as an official CISA-known exploited campaign based on the provided KEV finding. EPSS is a prediction with a falling trend, but public exploit availability and RED urgency align with active attacker interest. No vendor patch/fixed version information is available in the findings provided, so mitigation must rely on removal/upgrade to an alternative solution or vendor guidance.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS99th

Public exploit

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

2 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in

EPSS

50% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

22 events over 3484 days, from the signal feeds we watch.

2026-09-23EPSS band changemoderate → highepss band change
2026-09-21EPSS band changehigh → moderateepss band change
2026-09-06EPSS band changemoderate → highepss band change
2026-09-05EPSS band changehigh → moderateepss band change
2026-08-31EPSS band changemoderate → highepss band change
2026-08-29EPSS band changehigh → moderate

Affected products

ftpshellcommercial
- ftpshell clientOn-premSecurity Products / endpoint-av-edr

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.0 vector

Open in the CVSS calculator

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

Attack Vector NetworkExploitable remotely over the network without any special conditions
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required NoneNo authentication required — anyone can exploit this
User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

Confidentiality HighTotal information disclosure — all data in the component is compromised
Integrity HighTotal loss of integrity — attacker can modify any data in the component
Availability HighTotal denial of service — the component is completely unavailable