Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain low-privilege user account
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ExploitSubmit crafted SQL in request parameter
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ExecutionBackend query injection in Qsync Central
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ImpactRead or modify unauthorized database data
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Parameterized queries, prepared statements
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Persistence The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires the attacker to first possess a valid Qsync Central user account (PR:L) - the vulnerability cannot be triggered by a fully unauthenticated attacker. Given that, no user interaction is needed (UI:N) and the attack is network-reachable (AV:N) with low complexity (AC:L) against affected versions Qsync Central 5.0.0 through below 5.0.0.2. Limiting factors: the account prerequisite, exposure of the Qsync Central service to the attacker's network, and running an unpatched version prior to 5.0.0.2 (released 2025/07/31); environments that restrict account creation and network reachability or have patched are not exposed. |
| Impact | The vendor-supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N) scores 8.6 (High), indicating a network-reachable, low-complexity SQL injection that requires an authenticated user account (PR:L) and no user interaction, yielding high confidentiality and integrity impact with no availability impact. These signals are internally consistent with the description, which explicitly states a remote attacker must first gain a user account. The EPSS score is low at 0.09% (26th percentile), indicating a low modeled probability of exploitation in the near term. The CVE is NOT on CISA KEV and no public exploit code is referenced in the provided data, so there is no public exploit identified at time of analysis. The combination - authentication requirement plus low EPSS plus no POC/KEV - tempers the high CVSS: this is a credible but not urgent issue. It is a real priority only for environments where Qsync Central is internet-exposed and low-privilege accounts are easily obtainable (e.g., many user accounts, weak onboarding). The 'execute unauthorized code or commands' phrasing in the description is broader than a typical SQLi data-disclosure outcome; however, the vendor vector sets VA:N (no availability impact) and does not indicate a scope change, so the practical impact is best read as database read/write (confidentiality and integrity) rather than full OS command execution - this discrepancy between description wording and the CVSS vector should be verified with the vendor advisory QSA-25-35. |
| Exploit ScenarioDerived | An attacker who holds or obtains a low-privilege Qsync Central user account sends a crafted request containing malicious SQL to an injectable parameter, manipulating backend database queries to read or alter data beyond their authorization. No public exploit code is identified at time of analysis, and no user interaction is required once valid credentials are held. |
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Alert meAnalysisAIv2 – Oct 18, 2026
SQL injection in QNAP Qsync Central versions 5.0.0 through below 5.0.0.2 lets a remote attacker who already holds a valid Qsync Central user account run unauthorized code or commands on the underlying NAS with high confidentiality and integrity impact, though availability is not affected. The flaw is network-reachable and low-complexity but gated behind the account prerequisite (PR:L, authenticated), so unauthenticated internet exposure alone is not sufficient; EPSS is low (0.09%, 26th percentile) and no public exploit has been identified at time of analysis, with no CISA KEV listing. QNAP has released a vendor patch in Qsync Central 5.0.0.2 (2025/07/31).
Earlier versions of this analysis (1)
RemediationAI
Upgrade Qsync Central to 5.0.0.2 (2025/07/31) or later through App Center or the QNAP advisory at https://www.qnap.com/en/security-advisory/qsa-25-35 (QSA-25-35); this is the only complete fix, since the injection is in application code and cannot be closed by configuration alone. Where patching must be deferred, reduce exposure by restricting who can reach the Qsync Central interface - place the NAS management/sync ports behind VPN or an allowlisted admin network, or disable the Qsync Central service entirely if unused (side effect: sync clients stop working and users lose remote file synchronization until re-enabled). Tighten account provisioning so only trusted users hold Qsync Central accounts, since a valid account is the sole prerequisite for exploitation, and audit the local user list for stale or unnecessary accounts (side effect: reduced convenience for legitimate sync users). Enforce least privilege so non-admin sync accounts cannot chain the injection into higher-impact actions, and review database and Qsync service logs for anomalous query patterns or unexpected command activity from authenticated sessions as a detection measure. Note that patching only removes the injection path; credentials of any account that may have been used to exploit the flaw should be rotated.
Affected VersionsENISA
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Technical ContextAI · show details
Qsync Central is QNAP's NAS-hosted file synchronization service that manages shared folders, users and sync clients, and it exposes a web-facing management interface backed by a database. The reported weakness is CWE-89 (Improper Neutralization of Special Elements used in an SQL Command), meaning user-supplied input reaches a SQL query without adequate parameterization or escaping, allowing an attacker to alter query structure via crafted requests to the Qsync Central endpoints. The CPE cpe:2.3:a:qnap:qsync_central:*:*:*:*:*:*:*:* is unversioned but EUVD narrows the affected range to 5.0.0 through below 5.0.0.2. QNAP's CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N) scores 8.6 and matches our independent CVSS 3.1 assessment (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N): the injectable path is reachable over the network with no special preconditions and no user interaction, but requires the attacker to first authenticate with a legitimate Qsync Central account, which is why the privilege-required metric is the key mitigating factor rather than complexity or interaction. Because successful injection can alter database contents and, per QNAP, lead to execution of unauthorized code or commands, the practical consequence is corruption or disclosure of sync metadata and adjacent data plus potential command execution in the context of the Qsync service on the appliance.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Network SQL injection requiring a low-privilege account (PR:L) with no interaction; high confidentiality/integrity on the database, no availability impact and no scope change.
Primary rating from Vendor (qnapsecurity).
CVSS VectorVendor: qnapsecurity
Lifecycle Timeline
5DescriptionCVE.org
An SQL injection vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to execute unauthorized code or commands.
We have already fixed the vulnerability in the following version: Qsync Central 5.0.0.2 ( 2025/07/31 ) and later
Executive ViewAI
Qsync Central versions prior to 5.0.0.2 contain a SQL injection vulnerability (CVSS 8.8) that allows authenticated users to execute arbitrary code, potentially compromising data integrity and system availability. Organizations using Qsync Central must prioritize immediate patching to prevent account-based lateral movement and unauthorized command execution within their backup and synchronization infrastructure.
Apply vendor patch. If immediate patching is not feasible: implement strict network segmentation to limit Qsync Central access to trusted users only, enforce strong multi-factor authentication for all Qsync Central user accounts, monitor database query logs for suspicious SQL syntax patterns, and restrict user account creation to minimize the number of accounts that could be compromised to exploit this vulnerability.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
SQL injection exploits the way applications construct database queries by mixing user input directly into SQL statements.
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EUVD-2025-32451
NVD
CVE.org
EPSS
GitHub PoC
Exploit-DB