Cyber Posture

CVE-2024-53695

Critical

Published: 07 March 2025

Published
07 March 2025
Modified
16 January 2026
KEV Added
Patch
CVSS Score 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
EPSS Score 0.0079 74.0th percentile
Risk Priority 19 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2024-53695 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Qnap Hybrid Backup Sync. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 26.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 2 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Requires timely identification, reporting, and correction of the buffer overflow flaw, enabling patching to HBS 3 version 25.1.4.952 or later.

prevent

Implements memory protections like ASLR and DEP to prevent successful exploitation of buffer overflows via arbitrary memory modification or code execution.

prevent

Enforces validation of network inputs to block oversized or malformed data that triggers the buffer overflow vulnerability.

MITRE ATT&CK Enterprise TechniquesAI

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.
T1565.001 Stored Data Manipulation Impact
Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Remote buffer overflow in public-facing backup sync service enables T1190 for initial exploitation; arbitrary memory modification facilitates T1565.001 data tampering; process crashes enable T1499.004 DoS via application exploitation.

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

NVD Description

A buffer overflow vulnerability has been reported to affect HBS 3 Hybrid Backup Sync. If exploited, the vulnerability could allow remote attackers to modify memory or crash processes. We have already fixed the vulnerability in the following version: HBS 3…

more

Hybrid Backup Sync 25.1.4.952 and later

Deeper analysisAI

CVE-2024-53695 is a buffer overflow vulnerability (CWE-120, CWE-121) in HBS 3 Hybrid Backup Sync from QNAP, published on 2025-03-07. The flaw affects this backup synchronization software, earning a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H), indicating critical severity due to its potential for high impact on integrity and availability without confidentiality compromise.

Remote attackers can exploit the vulnerability over the network with low attack complexity, requiring no privileges, authentication, or user interaction. Exploitation enables arbitrary memory modification, potentially leading to data tampering or process crashes, which could disrupt backup operations or enable further compromise depending on the attacker's goals.

QNAP has mitigated the issue in HBS 3 Hybrid Backup Sync version 25.1.4.952 and later. Administrators should update affected systems immediately, as detailed in the vendor's security advisory at https://www.qnap.com/en/security-advisory/qsa-25-06.

Details

CWE(s)

Affected Products

qnap
hybrid backup sync
25.1.0.627 — 25.1.4.952

CVEs Like This One

CVE-2025-62842Same product: Qnap Hybrid Backup Sync
CVE-2025-48725Same product class: NAS / storage appliance
CVE-2025-59383Same product class: NAS / storage appliance
CVE-2025-48724Same product class: NAS / storage appliance
CVE-2025-52869Same product class: NAS / storage appliance
CVE-2025-48723Same product class: NAS / storage appliance
CVE-2025-52872Same product class: NAS / storage appliance
CVE-2025-52863Same product class: NAS / storage appliance
CVE-2025-52864Same product class: NAS / storage appliance
CVE-2025-52870Same product class: NAS / storage appliance

References