CVE-2025-7416 Overview
CVE-2025-7416 is a stack-based buffer overflow vulnerability in the Tenda O3V2 router running firmware version 1.0.0.12(3880). The flaw resides in the fromSysToolTime function within the /goform/setSysTimeInfo endpoint of the device's httpd web server. Attackers manipulate the Time argument to overflow a fixed-size stack buffer, corrupting adjacent memory and control flow data. The issue is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). The exploit has been publicly disclosed, increasing the likelihood of opportunistic attacks against exposed devices.
Critical Impact
Remote attackers with low-privileged authentication can corrupt stack memory on Tenda O3V2 devices, potentially achieving arbitrary code execution or denial of service against the router.
Affected Products
- Tenda O3 router (hardware version 2.0)
- Tenda O3V2 firmware 1.0.0.12(3880)
- httpd component handling /goform/setSysTimeInfo
Discovery Timeline
- 2025-07-10 - CVE-2025-7416 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-7416
Vulnerability Analysis
The vulnerability exists in the fromSysToolTime handler invoked when an HTTP request reaches the /goform/setSysTimeInfo URI on the Tenda O3V2 httpd daemon. The handler reads the Time parameter from the request body and copies it into a fixed-size stack buffer without enforcing a length boundary. Supplying an oversized Time value overruns the buffer and overwrites adjacent stack data, including saved return addresses on MIPS or ARM-based router architectures. According to the published EPSS value of 0.761%, scanning and exploitation interest is moderate for this class of embedded-device flaw.
Root Cause
The root cause is missing input length validation before a memory copy operation, consistent with [CWE-119]. The fromSysToolTime function trusts attacker-controlled input from the HTTP request and writes it directly into a stack-allocated buffer. Embedded web interfaces in consumer routers commonly omit bounds checks on goform parameters, and Tenda firmware images typically ship without stack canaries or position-independent execution, making the overflow directly exploitable.
Attack Vector
An attacker sends a crafted HTTP POST request to the /goform/setSysTimeInfo endpoint of the router's management interface, with an oversized value in the Time field. Exploitation requires network reachability to the management interface and low-privileged credentials. Successful exploitation can crash the httpd process, disrupt routing functionality, or hijack control flow for code execution. Refer to the GitHub Vulnerability Report and GitHub Proof of Concept for technical reproduction details.
No verified exploitation code is reproduced here. See the linked advisory and VulDB #315876 for technical analysis.
Detection Methods for CVE-2025-7416
Indicators of Compromise
- Unexpected restarts or crashes of the httpd service on Tenda O3V2 routers
- HTTP POST requests to /goform/setSysTimeInfo containing abnormally long Time parameter values
- Configuration changes to system time settings from unrecognized source IP addresses
- Outbound connections from the router to attacker-controlled infrastructure following management-interface traffic
Detection Strategies
- Inspect HTTP traffic destined for the router management interface for requests targeting /goform/setSysTimeInfo with oversized payload fields
- Deploy network intrusion detection signatures that flag Time parameter lengths exceeding expected bounds
- Correlate device crash events with preceding HTTP requests from the same source
Monitoring Recommendations
- Forward router syslog and httpd crash telemetry to a centralized logging platform for analysis
- Alert on any external access to the device administration port from outside the management VLAN
- Track configuration drift on the device, including unauthorized changes to NTP and system time fields
How to Mitigate CVE-2025-7416
Immediate Actions Required
- Restrict access to the router's management interface to trusted internal networks and block external WAN-side administration
- Change default and weak administrative credentials, since exploitation requires low-privileged authentication
- Audit currently deployed Tenda O3 devices for firmware version 1.0.0.12(3880) and isolate affected units
Patch Information
No vendor patch was referenced in the published advisory at the time of disclosure. Monitor the Tenda Official Website for firmware updates addressing the fromSysToolTime handler. Replace end-of-life hardware if no fix is forthcoming.
Workarounds
- Disable remote administration over WAN and restrict the management UI to a dedicated management VLAN
- Place the router behind a firewall that filters HTTP requests to /goform/setSysTimeInfo from untrusted sources
- Where feasible, replace the affected Tenda O3V2 device with a supported model that receives current security patches
# Example firewall rule to block external access to the Tenda management interface
iptables -A INPUT -p tcp --dport 80 -i wan0 -j DROP
iptables -A INPUT -p tcp --dport 443 -i wan0 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
