CVE-2025-14198: Verysync Information Disclosure Flaw

CVE-2025-14198 Overview

CVE-2025-14198 is an information disclosure vulnerability affecting Verysync (微力同步) version 2.21.3. The flaw exists in the Web Administration Module, specifically in the /safebrowsing/clientreport/download?key=dummytoken endpoint. Attackers can exploit this issue remotely without authentication or user interaction. Manipulation of the vulnerable endpoint results in disclosure of sensitive information from the affected system.

Public exploit details are available, increasing the likelihood of opportunistic attacks. The vendor was contacted before public disclosure but did not respond. The vulnerability is classified under [CWE-200] (Exposure of Sensitive Information to an Unauthorized Actor).

Critical Impact
Remote, unauthenticated attackers can extract sensitive information from Verysync 2.21.3 installations by manipulating a Web Administration Module endpoint. No vendor patch is available.

Affected Products

Verysync (微力同步) version 2.21.3
Verysync Web Administration Module
Deployments exposing the Verysync management interface to untrusted networks

Discovery Timeline

2025-12-07 - CVE-2025-14198 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-14198

Vulnerability Analysis

The vulnerability resides in the Verysync Web Administration Module. Requests to /safebrowsing/clientreport/download accepting a key parameter such as dummytoken return data that should not be accessible to unauthenticated users. The endpoint fails to enforce proper authorization before serving the response.

The attack is network-based and requires no privileges or user interaction. This aligns with the CWE-200 classification for improper exposure of sensitive information. Public exploit details lower the barrier for opportunistic attackers scanning for exposed Verysync instances.

Root Cause

The root cause is missing or insufficient authorization checks on the /safebrowsing/clientreport/download handler. The endpoint appears to accept a static or predictable key value and returns client report data without validating the requester's session or privileges. This is a classic broken access control pattern applied to an administrative diagnostic endpoint.

Attack Vector

An attacker sends an HTTP GET request to the vulnerable endpoint over the network. Because Verysync is commonly deployed as a file synchronization service accessible via a web interface, exposed instances may be reachable from the internet or across internal network segments. The server responds with information that should be restricted to administrators.

No verified proof-of-concept code is published in structured form. See the GitHub Issue Report and VulDB entry #334618 for technical context.

Detection Methods for CVE-2025-14198

Indicators of Compromise

HTTP requests to the path /safebrowsing/clientreport/download containing a key query parameter, particularly key=dummytoken
Unusual outbound data volume from Verysync hosts following unauthenticated GET requests to the administration module
Access to Verysync management endpoints from IP addresses outside expected administrative ranges

Detection Strategies

Deploy web application firewall (WAF) rules that flag or block requests to /safebrowsing/clientreport/download from untrusted sources
Enable verbose access logging on the Verysync Web Administration Module and forward logs to a centralized SIEM
Correlate unauthenticated requests to administrative paths with subsequent lateral movement or credential use

Monitoring Recommendations

Monitor for repeated requests to the Verysync administration interface without prior authentication events
Alert on any external network access to Verysync management ports
Baseline normal administrative traffic patterns and flag deviations for review

How to Mitigate CVE-2025-14198

Immediate Actions Required

Restrict network access to the Verysync Web Administration Module using firewall rules or reverse proxy access controls
Place Verysync administration interfaces behind a VPN or authenticated gateway
Audit access logs for prior requests to /safebrowsing/clientreport/download and investigate any hits
Rotate any credentials, tokens, or sync keys that may have been exposed through the endpoint

Patch Information

As of the last NVD update on 2026-06-17, no vendor patch has been published. The vendor did not respond to disclosure attempts. Track updates through the VulDB CTI entry #334618 and the upstream GitHub issue for remediation availability.

Workarounds

Block external HTTP/HTTPS access to the /safebrowsing/clientreport/ path at the network perimeter or reverse proxy
Bind the Verysync administration interface to localhost or a management-only network interface
Require IP allow-listing for administrative access to the Verysync service
Consider isolating Verysync 2.21.3 hosts until an official fix is released or migrating to an alternative synchronization solution

bash

# Example nginx reverse proxy rule to block the vulnerable endpoint
location ~* ^/safebrowsing/clientreport/ {
    deny all;
    return 403;
}

# Example iptables rule restricting Verysync admin port to a trusted subnet
iptables -A INPUT -p tcp --dport 8886 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8886 -j DROP