CVE-2025-63685Public exploit

Code execution via unqualified regsvr32.exe lookup

Published Nov 20, 2025 · Updated Nov 21, 2025

DLL search-order hijacking in Quark Cloud Drive 3.23.2 allows local users to execute code when a user launches the Windows installer. The installer invokes regsvr32.exe without an absolute system path or signature validation, so Windows resolves an attacker-controlled file from the installer's directory. Exploitation requires write access to that directory and user interaction; the payload runs with the installer's privileges, including SYSTEM when elevated.

CVSS severity9.8
Critical
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DLL search-order hijacking in Quark Cloud Drive 3.23.2 allows local users to execute code when a user launches the Windows installer. The installer invokes regsvr32.exe without an absolute system path or signature validation, so Windows resolves an attacker-controlled file from the installer's directory. Exploitation requires write access to that directory and user interaction; the payload runs with the installer's privileges, including SYSTEM when elevated.

The record

CVE
CVE-2025-63685
Published
Nov 20, 2025
Updated
Nov 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-491, T1574.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-491Public cloneable() Method Without Final ('Object Hijack')
T1574.001DLL Search Order Hijacking

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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