CVE-2025-6146 Overview
CVE-2025-6146 is a buffer overflow vulnerability affecting TOTOLINK X15 routers running firmware version 1.0.0-B20230714.1105. The flaw resides in the HTTP POST request handler that processes requests to the /boafrm/formSysLog endpoint. An attacker can manipulate the submit-url argument to overflow a fixed-size buffer in the device's web server. The vulnerability is exploitable remotely over the network and the exploit details have been disclosed publicly. The weakness is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer.
Critical Impact
Remote attackers with low privileges can trigger memory corruption in the router's HTTP service, potentially leading to arbitrary code execution or denial of service on affected TOTOLINK X15 devices.
Affected Products
- TOTOLINK X15 router hardware
- TOTOLINK X15 firmware version 1.0.0-B20230714.1105
- Deployments exposing the device web management interface to untrusted networks
Discovery Timeline
- 2025-06-17 - CVE-2025-6146 published to NVD with public proof-of-concept disclosure
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-6146
Vulnerability Analysis
The vulnerability exists in the formSysLog handler within the boafrm web interface module of the TOTOLINK X15 firmware. The handler processes HTTP POST requests targeting /boafrm/formSysLog and reads attacker-controlled values from request parameters. The submit-url parameter is copied into a fixed-size stack buffer without proper length validation. Sending an oversized value overflows the buffer and corrupts adjacent memory, including saved return addresses on the stack. Successful exploitation can crash the embedded HTTP daemon or hijack control flow to execute attacker-supplied instructions in the context of the web server process.
Root Cause
The root cause is an unsafe string copy operation that lacks bounds checking on the submit-url POST parameter. The MIPS-based boafrm binary, derived from the Boa web server, does not enforce a maximum length before writing user-supplied data into a stack-allocated buffer. This pattern of missing length validation is recurring across multiple TOTOLINK firmware components and is tracked as [CWE-119].
Attack Vector
Exploitation requires network reachability to the device management interface and a low-privilege authenticated session. An attacker crafts an HTTP POST request to /boafrm/formSysLog containing an oversized submit-url parameter value. When the firmware processes the request, the overflow corrupts the call stack of the web server. No user interaction is required beyond submitting the request. Devices exposing the management interface to the WAN or to untrusted LAN segments are at elevated risk. Public proof-of-concept details are referenced in the GitHub PoC Repository and the VulDB #312621 entry.
// No verified exploit code is published in this article.
// Refer to the linked PoC for technical reproduction details.
Detection Methods for CVE-2025-6146
Indicators of Compromise
- HTTP POST requests to /boafrm/formSysLog containing abnormally long submit-url parameter values
- Unexpected restarts or crashes of the router's web management daemon
- Outbound connections from the router to unfamiliar hosts following suspicious HTTP traffic
- Configuration changes or new firewall rules not initiated by an administrator
Detection Strategies
- Inspect web server and reverse proxy logs for POST requests to /boafrm/formSysLog with parameter lengths exceeding expected sizes
- Deploy network IDS signatures that flag oversized submit-url values in HTTP request bodies addressed to TOTOLINK device IPs
- Correlate router crash events with preceding HTTP traffic to identify exploitation attempts
Monitoring Recommendations
- Forward router syslog and HTTP access logs to a centralized logging platform for retention and analysis
- Alert on any administrative access to the router from non-management subnets or external IP ranges
- Monitor for repeated authentication events to the device followed by POSTs to boafrm endpoints
How to Mitigate CVE-2025-6146
Immediate Actions Required
- Restrict access to the router's HTTP management interface to trusted internal management hosts only
- Disable WAN-side access to the device administration interface until a vendor patch is available
- Rotate administrative credentials on affected TOTOLINK X15 devices to reduce risk of low-privilege account abuse
- Inventory environments to identify any TOTOLINK X15 units running firmware 1.0.0-B20230714.1105
Patch Information
At the time of publication, no vendor-supplied patch is referenced in the NVD entry for CVE-2025-6146. Administrators should monitor the TOTOLINK Official Website for firmware updates addressing the formSysLog handler and apply them as soon as they become available.
Workarounds
- Place affected routers behind a firewall that blocks inbound HTTP and HTTPS to the management interface from untrusted networks
- Segment vulnerable devices onto an isolated VLAN with strict ACLs limiting which hosts may reach the web interface
- Where feasible, replace affected TOTOLINK X15 units with devices that receive active security maintenance
# Example iptables rule restricting access to the router web UI
# Replace 192.0.2.10 with the trusted management host and 198.51.100.1 with the router IP
iptables -A FORWARD -p tcp -d 198.51.100.1 --dport 80 -s 192.0.2.10 -j ACCEPT
iptables -A FORWARD -p tcp -d 198.51.100.1 --dport 80 -j DROP
iptables -A FORWARD -p tcp -d 198.51.100.1 --dport 443 -s 192.0.2.10 -j ACCEPT
iptables -A FORWARD -p tcp -d 198.51.100.1 --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
