Qsync Central: Improper Link Resolution Before File Access
CVE-2024-50404 is a high-severity improper link resolution before file access vulnerability in Qsync Central from QNAP, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 4.4.0.16_20240819 ( 2024/08/19 ) as the first without the flaw, so updating Qsync Central to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.43% chance of exploitation within 30 days, higher than 74% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Qsync Central to 4.4.0.16_20240819 ( 2024/08/19 ) or a later version.
- Read the advisory on qnap.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| QNAP | Qsync Central | 4.4.x.x up to, but not including, 4.4.0.16_20240819 ( 2024/08/19 ) | 4.4.0.16_20240819 ( 2024/08/19 ) |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.8 | Medium | CNA (qnapsecurity.com.tw) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A link following vulnerability has been reported to affect Qsync Central. If exploited, the vulnerability could allow remote attackers who have gained user access to traverse the file system to unintended locations. We have already fixed the vulnerability in the following versions: Qsync Central 4.4.0.16_20240819 ( 2024/08/19 ) and later
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Link Resolution Before File Access
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How developers prevent this class of flaw
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More Improper Link Resolution Before File Access vulnerabilities (CWE-59)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Qsync Central
- 7.2 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
Recent Improper Link Resolution Before File Access vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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