Cyber Resilience

CVE-2024-53695

Memory Safety in Qnap Hybrid Backup Sync 25.1.0.627 – 25.1.4.952

Published
07 March 2025
Modified
16 January 2026
Patch / advisory
CVSS Score v4 6.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0050 41th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2024-53695 is a medium-severity Classic Buffer Overflow (CWE-120) vulnerability in Qnap Hybrid Backup Sync. Its CVSS base score is 6.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 41th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

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

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.

EU & UK References

Vulnerability Data

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

CWE(s)

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.
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.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

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CVE-2024-27129Same product class: NAS / storage appliance

Affected Assets

qnap
hybrid backup sync
25.1.0.627 — 25.1.4.952

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and analysis can find missing size checks before deployment.

Input validation directly enforces size checks before buffer copies.

Memory-protection mechanisms limit the ability to execute injected code after a stack overflow.

Engineering principles require bounds checking and safe buffer handling in design.

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 directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

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.

prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

finds

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

none

Change-management gates can enforce security reviews that catch buffer issues.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248594 OL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution. prevents CWE-121
Oracle Linux 9 (1 rule)
  • V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-121

References