CVE-2019-25361

CriticalPublic PoC

Published: 18 February 2026

Published

18 February 2026

Modified

15 April 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0027 50.1th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2019-25361 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Ayukov NFTP (inferred from references). Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 49.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Directly remediates the buffer overflow vulnerability in Ayukov NFTP client 1.71 by applying patches or upgrading to a non-vulnerable version.

SI-10 Information Input Validation good match

prevent

Validates the size and structure of incoming SYST command payloads to prevent buffer overflows from oversized inputs.

SI-16 Memory Protection good match

prevent

Implements memory protections like ASLR, DEP, and stack canaries to block arbitrary code execution even if the buffer overflow occurs.

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

Why these techniques?

Buffer overflow in FTP client enables remote arbitrary code execution via Exploitation for Client Execution (T1203).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

Ayukov NFTP client 1.71 contains a buffer overflow vulnerability in the SYST command handling that allows remote attackers to execute arbitrary code. Attackers can send a specially crafted SYST command with oversized payload to trigger a buffer overflow and execute…

a bind shell on port 5150.

Deeper analysisAI

CVE-2019-25361 is a buffer overflow vulnerability in the Ayukov NFTP client version 1.71, specifically within the SYST command handling. This stack-based buffer overflow, mapped to CWE-121, allows remote attackers to execute arbitrary code by sending a specially crafted SYST command with an oversized payload. The vulnerability received a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), highlighting its critical severity due to high confidentiality, integrity, and availability impacts.

Remote attackers can exploit this vulnerability without authentication, privileges, or user interaction, connecting over the network to a vulnerable NFTP client instance. By transmitting a malformed SYST command, the oversized payload overflows the buffer, enabling arbitrary code execution, such as establishing a bind shell on TCP port 5150 for remote control of the affected system.

Advisories from VulnCheck detail the buffer overflow in Ayukov NFTP's SYST handling, while Exploit-DB provides a corresponding proof-of-concept exploit (ID 47576). The official Ayukov NFTP site at ayukov.com/nftp/ is referenced, though specific patch or mitigation guidance is not outlined in the available descriptions.