CVE-2025-61941 Overview
CVE-2025-61941 is a path traversal vulnerability [CWE-22] affecting Buffalo WXR9300BE6P series wireless router firmware versions prior to Ver.1.10. An administrative user authenticated to the device can alter arbitrary files on the underlying system by manipulating file path parameters. The flaw also enables execution of arbitrary operating system commands when crafted file content is written to sensitive locations. Buffalo published an advisory on October 14, 2025, and the Japan Vulnerability Notes (JVN) database coordinated public disclosure.
Critical Impact
Authenticated administrators can overwrite arbitrary files on the router and chain the issue into arbitrary OS command execution, compromising the integrity and availability of the device.
Affected Products
- Buffalo WXR9300BE6P series firmware versions prior to Ver.1.10
- Wireless routers running the vulnerable management web interface
- Deployments exposing the administrative interface to untrusted networks
Discovery Timeline
- 2025-10-14 - Buffalo publishes security news update on the issue
- 2025-10-15 - CVE-2025-61941 published to NVD
- 2026-04-15 - Last updated in NVD database
Technical Details for CVE-2025-61941
Vulnerability Analysis
The vulnerability resides in the administrative web interface of the WXR9300BE6P router. Input fields that accept file paths fail to canonicalize and validate user-supplied values. An authenticated administrator can supply traversal sequences such as ../ to escape the intended directory and reference files outside the expected scope. Because the affected handler writes to the supplied path, the attacker can overwrite system files. When the overwritten file is interpreted by a shell or service, the attacker achieves arbitrary OS command execution on the router. The issue is classified as [CWE-22] Improper Limitation of a Pathname to a Restricted Directory. The current EPSS probability is 0.082%, indicating a low observed exploitation likelihood at this time.
Root Cause
The firmware does not enforce a strict allow-list or canonical path check before writing user-controlled data to disk. Path normalization is either missing or performed after authorization checks, so traversal sequences are passed through to file write routines unchanged.
Attack Vector
The attack requires network access to the router's management interface and valid administrator credentials. After authentication, the attacker submits a request to the vulnerable endpoint with a traversal-laden path parameter. The router writes attacker-controlled content to an arbitrary location, and execution follows when the targeted file is subsequently invoked by the system.
No verified public exploit code is available. See the JVN Security Vulnerability Report and the Buffalo Security News Update for vendor-provided technical detail.
Detection Methods for CVE-2025-61941
Indicators of Compromise
- Administrative web requests containing ../, ..\, or URL-encoded equivalents (%2e%2e%2f) in path or filename parameters
- Unexpected modification timestamps on router configuration, startup scripts, or /etc files
- Outbound connections from the router to unfamiliar hosts following administrative sessions
- Unscheduled reboots or service restarts on the WXR9300BE6P device
Detection Strategies
- Inspect HTTP/HTTPS traffic to the router management interface for traversal patterns in POST bodies and query strings
- Correlate administrator login events with file upload or configuration write actions occurring outside change windows
- Compare firmware file integrity against known-good baselines after administrative sessions
Monitoring Recommendations
- Forward router syslog and authentication events to a centralized log repository for retention and review
- Alert on administrative logins from non-management subnets or unexpected geographies
- Track failed and successful firmware update attempts to identify tampering with the upgrade workflow
How to Mitigate CVE-2025-61941
Immediate Actions Required
- Upgrade WXR9300BE6P firmware to Ver.1.10 or later as released by Buffalo
- Restrict access to the router administrative interface to trusted management networks only
- Rotate administrator credentials and disable any unused administrative accounts
- Audit recent administrative sessions and configuration changes for signs of tampering
Patch Information
Buffalo addressed the vulnerability in firmware Ver.1.10. Refer to the Buffalo Security News Update for download links and update instructions, and the JVN Security Vulnerability Report for coordinated disclosure details.
Workarounds
- Disable remote management on the WAN interface until the firmware update is applied
- Place the router management interface behind a firewall rule that limits source addresses to administrative workstations
- Enforce strong, unique administrator passwords and multi-factor authentication on any jump host used for router administration
# Configuration example: restrict management access at the network boundary
# Allow only the management subnet to reach the router admin interface (HTTPS)
iptables -A FORWARD -s 192.0.2.0/24 -d <router-ip> -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d <router-ip> -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
