CVE-2017-15271

MEDIUM

PSFTPd 10.0.4 Build 729 - Unauthenticated Use-After-Free via Crafted SSH Identification String

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2017-15271. PoCs published by X41 D-Sec GmbH.

AI-analyzed exploit summary This is a security advisory detailing multiple vulnerabilities in PSFTPd Windows FTP Server, including a use-after-free (CVE-2017-15271), log injection (CVE-2017-15270), plaintext password storage (CVE-2017-15272), and FTP bounce scan (CVE-2017-15269). The advisory provides technical details, proof-of-concept steps, and mitigation guidance.

Description

A use-after-free issue could be triggered remotely in the SFTP component of PSFTPd 10.0.4 Build 729. This issue could be triggered prior to authentication. The PSFTPd server did not automatically restart, which enabled attackers to perform a very effective DoS attack against this service. By sending a crafted SSH identification / version string to the server, a NULL pointer dereference could be caused, apparently because of a race condition in the window message handling, performing the cleanup for invalid connections. This incorrect cleanup code has a use-after-free.

Exploits (1)

exploitdb WRITEUP
by X41 D-Sec GmbH · textdoswindows
https://www.exploit-db.com/exploits/43144

This is a security advisory detailing multiple vulnerabilities in PSFTPd Windows FTP Server, including a use-after-free (CVE-2017-15271), log injection (CVE-2017-15270), plaintext password storage (CVE-2017-15272), and FTP bounce scan (CVE-2017-15269). The advisory provides technical details, proof-of-concept steps, and mitigation guidance.

Classification
Writeup 100%
Attack Type
Dos | Info Leak | Other
Complexity
Moderate
Reliability
Reliable
Target: PSFTPd Windows FTP Server 10.0.4 Build 729
No auth needed
Prerequisites: Network access to the target server · SFTP/FTP service exposed
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (4)

Core 4
Core References
Third Party Advisory, VDB Entry mailing-list x_refsource_bugtraq
http://www.securityfocus.com/archive/1/541518/100/0/threaded
Third Party Advisory x_refsource_misc
https://www.x41-dsec.de/lab/advisories/x41-2017-006-psftpd/
Third Party Advisory, VDB Entry exploit x_refsource_exploit-db
https://www.exploit-db.com/exploits/43144/

Scores

CVSS v3 5.9
EPSS 0.0874
EPSS Percentile 94.5%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-416
Status published
Products (1)
psftp/psftpd 10.0.4
Published Nov 15, 2017
Tracked Since Feb 18, 2026