Quark Cloud Drive: Public cloneable() Method Without Final
CVE-2025-63685 is a critical-severity public cloneable() method without final vulnerability in Quark Cloud Drive from Quark, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Quark Cloud Drive versions: 3.23.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Quark Cloud Drive you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Quark | Quark Cloud Drive | 3.23.2 | Not stated |
Version data comes from NVD's product matching. 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
- NoneNo account or login is needed.
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Quark Cloud Drive v3.23.2 has a DLL Hijacking vulnerability. This vulnerability stems from the insecure loading of system libraries. Specifically, the application does not validate the path or signature of [regsvr32.exe] it loads. An attacker can place a crafted malicious DLL in the application's startup directory, which will be loaded and executed when the user launches the program.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Public cloneable() Method Without Final
A class has a cloneable() method that is not declared final, which allows an object to be created without calling the constructor. This can cause the object to be in an unexpected state.
More Public cloneable() Method Without Final vulnerabilities (CWE-491)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- github.com/QIU-DIE/CVE/issues/5Exploit, Issue Tracking, Third Party Advisory
Recent Public cloneable() Method Without Final vulnerabilities
- 8.6 High severity
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