Cyber Resilience

CVE-2023-51713

Memory Safety in Proftpd ≤ 1.3.8a

Public PoCMemory Safety
Published
22 December 2023
Modified
03 November 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.042 90th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2023-51713 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Proftpd Proftpd. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 10% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

ProFTPD versions prior to 1.3.8a contain a one-byte out-of-bounds read in the make_ftp_cmd function within main.c. The flaw stems from incorrect handling of quote and backslash characters in FTP command processing and is tracked as CWE-125. It produces a daemon crash with no confidentiality or integrity impact, corresponding to a CVSS 3.1 base score of 7.5.

An unauthenticated remote attacker can send a crafted FTP command containing specific quote or backslash sequences to trigger the read. Successful exploitation results only in denial of service through an immediate process termination; no code execution or data exposure has been demonstrated.

The project’s NEWS file and associated GitHub issue confirm that the defect is resolved in release 1.3.8a. Administrators are advised to upgrade ProFTPD instances to that version or later.

The CVE carries an EPSS score that reached a peak of 0.7339, indicating notable exploitation interest after public disclosure.

EU & UK References

Vulnerability Data

make_ftp_cmd in main.c in ProFTPD before 1.3.8a has a one-byte out-of-bounds read, and daemon crash, because of mishandling of quote/backslash semantics.

CWE(s)
CWE-125

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-63090Same product: Proftpd Proftpd
CVE-2026-53994Same product: Proftpd Proftpd
CVE-2026-63091Same product: Proftpd Proftpd
CVE-2026-42167Same product: Proftpd Proftpd
CVE-2026-35025Same product: Proftpd Proftpd
CVE-2026-23406Shared CWE-125
CVE-2025-37846Shared CWE-125
CVE-2024-53147Shared CWE-125
CVE-2024-11561Shared CWE-125
CVE-2024-47402Shared CWE-125

Affected Assets

proftpd
proftpd
≤ 1.3.8a

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

A.8.26 Application security requirements partial match
prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References