CVE-2026-10187 Overview
CVE-2026-10187 is a stack-based buffer overflow vulnerability in the Totolink N300RH router running firmware version 6.1c.1353_B20190305. The flaw resides in the setWiFiBasicConfig function within the wireless.so library, which is reachable through the Web Management Interface. Attackers can trigger the overflow by manipulating the KeyStr argument, leading to memory corruption on the stack. The vulnerability is remotely exploitable over the network and requires no authentication or user interaction. A public exploit has been disclosed, increasing the likelihood of opportunistic attacks against exposed devices.
Critical Impact
Unauthenticated remote attackers can corrupt stack memory through the Web Management Interface, potentially achieving arbitrary code execution on the router and full device compromise.
Affected Products
- Totolink N300RH router
- Firmware version 6.1c.1353_B20190305
- wireless.so component exposed via the Web Management Interface
Discovery Timeline
- 2026-05-31 - CVE-2026-10187 published to NVD
- 2026-06-01 - Last updated in NVD database
Technical Details for CVE-2026-10187
Vulnerability Analysis
The vulnerability is classified under [CWE-119] Improper Restriction of Operations within the Bounds of a Memory Buffer. The setWiFiBasicConfig function in wireless.so handles wireless configuration requests submitted through the Web Management Interface. When processing the KeyStr parameter, the function fails to validate the length of attacker-supplied input before copying it into a fixed-size stack buffer.
This improper boundary check allows an attacker to overwrite adjacent stack memory, including saved return addresses and function pointers. On embedded MIPS or ARM-based routers like the N300RH, successful exploitation typically leads to control of the program counter and arbitrary code execution under the privileges of the web server process, which usually runs as root.
The attack surface is broad because the vulnerable endpoint is part of the router's administrative web interface. Devices with the management interface exposed to the WAN are directly reachable, while LAN-side attackers can reach the endpoint from any device on the local network.
Root Cause
The root cause is the absence of bounds checking on the KeyStr argument prior to a memory copy operation into a fixed-size stack buffer inside setWiFiBasicConfig. The function trusts client-supplied input length, allowing oversized values to overflow the destination buffer.
Attack Vector
An attacker submits a crafted HTTP request to the router's Web Management Interface containing an overlong KeyStr value. The request reaches setWiFiBasicConfig in wireless.so, where the unchecked copy corrupts the stack. The attack requires network access to the management interface and no credentials. A public exploit has been released, lowering the barrier for exploitation.
No verified proof-of-concept code is reproduced here. Technical details are available via the VulDB entry for CVE-2026-10187 and the associated VulDB vulnerability record #367468.
Detection Methods for CVE-2026-10187
Indicators of Compromise
- HTTP POST requests to the router's Web Management Interface containing unusually long KeyStr parameter values
- Unexpected reboots, crashes, or service interruptions on the httpd or web management process of the N300RH
- Outbound connections from the router to unfamiliar IP addresses following administrative interface access
- New or modified firewall, DNS, or routing configurations not initiated by an administrator
Detection Strategies
- Inspect web server logs for requests targeting wireless configuration endpoints with abnormally large payload sizes
- Monitor network traffic for HTTP requests to the router management interface from untrusted sources, especially WAN-side
- Deploy network intrusion detection signatures that flag oversized KeyStr parameter values in HTTP request bodies
Monitoring Recommendations
- Continuously monitor whether the router's management interface is exposed to the internet using external attack surface scans
- Alert on configuration changes to wireless settings outside of approved maintenance windows
- Track firmware version inventory across managed Totolink devices to identify unpatched units
How to Mitigate CVE-2026-10187
Immediate Actions Required
- Restrict access to the Web Management Interface to trusted LAN segments and disable WAN-side administration
- Place affected Totolink N300RH devices behind a firewall that blocks inbound HTTP/HTTPS to the router's management port
- Change default and current administrative credentials on all Totolink N300RH devices to limit lateral risk
- Consider replacing affected devices if the vendor does not provide a firmware update
Patch Information
No vendor-supplied patch is referenced in the available advisory data. Consult the Totolink official website for firmware update availability and review the VulDB CVE-2026-10187 entry for the latest remediation guidance.
Workarounds
- Disable remote management of the router so the Web Management Interface is unreachable from the WAN
- Segment the router's management VLAN and apply ACLs that permit administrative access only from designated workstations
- Monitor for and block HTTP requests carrying oversized KeyStr values at an upstream web application firewall or IDS/IPS
# Example ACL concept: restrict management interface to a single admin host
# Adapt syntax to your firewall platform
deny tcp any any eq 80
deny tcp any any eq 443
permit tcp host 192.0.2.10 any eq 80
permit tcp host 192.0.2.10 any eq 443
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
