How severe is CVE-2024-53695?

CVE-2024-53695 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2024-53695 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-53695?

CVE-2024-53695 affects Qnap Hybrid Backup Sync. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2024-53695?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2024-53695 have an EU (EUVD) identifier?

Yes. CVE-2024-53695 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-54243.

When was CVE-2024-53695 published?

CVE-2024-53695 was published on 2025-03-07 and last updated on 2026-06-17.

CVE-2024-53695

CVE-2024-53695 is a critical-severity vulnerability in Qnap Hybrid Backup Sync with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 6.3
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-54243
Weakness: CWE-120
Affected product: Qnap Hybrid Backup Sync
Published: 2025-03-07
Last modified: 2026-06-17

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 Hybrid Backup Sync 25.1.4.952 and later

Frequently asked questions

What is CVE-2024-53695?: 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 Hybrid Backup Sync 25.1.4.952 and later
How severe is CVE-2024-53695?: CVE-2024-53695 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2024-53695 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-53695?: CVE-2024-53695 affects Qnap Hybrid Backup Sync. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-53695?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2024-53695 have an EU (EUVD) identifier?: Yes. CVE-2024-53695 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-54243.
When was CVE-2024-53695 published?: CVE-2024-53695 was published on 2025-03-07 and last updated on 2026-06-17.

References

https://www.qnap.com/en/security-advisory/qsa-25-06

Affected products (1)

cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:*

More vulnerabilities in Qnap Hybrid Backup Sync

CVE-2021-28799 — Critical (CVSS 10.0): An improper authorization vulnerability has been reported to affect QNAP NAS running HBS 3 (Hybrid Backup Sync. ) If…
CVE-2024-50388 — Critical (CVSS 9.8): An OS command injection vulnerability has been reported to affect HBS 3 Hybrid Backup Sync. If exploited, the…
CVE-2021-28809 — Critical (CVSS 9.8): An improper access control vulnerability has been reported to affect certain legacy versions of HBS 3. If exploited,…
CVE-2025-62842 — High (CVSS 7.8): An external control of file name or path vulnerability has been reported to affect HBS 3 Hybrid Backup Sync. If an…
CVE-2025-62840 — Low (CVSS 3.3): A generation of error message containing sensitive information vulnerability has been reported to affect HBS 3 Hybrid…

All CVEs affecting Qnap Hybrid Backup Sync →

Other CWE-120 (Classic Buffer Overflow) vulnerabilities

CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
CVE-2026-24823 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in FASTSHIFT…
CVE-2026-24810 — Critical (CVSS 10.0): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in rethinkdb (src/cjson modules).…
CVE-2026-24800 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in tildearrow…
CVE-2025-9962 — Critical (CVSS 10.0): A buffer overflow vulnerability in Novakon P series allows attackers to gain root permission without prior…
CVE-2010-10016 — Critical (CVSS 10.0): BS.Player version 2.57 (build 1051) contains a vulnerability in its playlist import functionality. When processing .m3u…

Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →