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The vulnerability, identified as CVE-2025-70238, is a stack-based buffer overflow found in the D-Link DIR-513 router running firmware version 1.10. The issue resides in the web server’s handling of POST requests to the endpoint /goform/formSetWAN_Wizard52. Specifically, the `curTime` parameter in the request body is copied into a fixed-size stack buffer using a function like `sprintf` without proper bounds checking. By supplying an overly long string for the `curTime` parameter, an attacker can overwrite adjacent memory on the stack. This memory corruption can be leveraged to hijack the program’s execution flow, potentially allowing for arbitrary code execution on the device. Public proof-of-concept exploits are available, and since the product is end-of-life, no official patch will be released.
Platform: D-Link DIR-513
Version: v1.10
Vulnerability: Stack Buffer Overflow
Severity: Critical
Date: 2026-03-09
Prediction: No patch expected
What Undercode Say:
Analytics:
The disclosure of CVE-2025-70238 follows a pattern of multiple buffer overflow vulnerabilities being reported in the end-of-life D-Link DIR-513 router. Given the availability of public proof-of-concept (PoC) exploits on platforms like GitHub and the lack of vendor support, active scanning for vulnerable devices is likely occurring. The attack vector is remote and requires no authentication, making it highly automatable.
How Exploit:
A basic exploit would involve sending a crafted POST request to the vulnerable endpoint. The `curTime` parameter is filled with a malicious payload designed to overflow the stack and overwrite the return address.
!/bin/bash
Example exploitation concept using curl
TARGET="http://<ROUTER_IP>/goform/formSetWAN_Wizard52"
Payload: A large string of 'A's to cause overflow, then a return address (e.g., 0xdeadbeef)
In a real exploit, this would be replaced with shellcode.
PAYLOAD="curTime=$(printf 'A%.0s' {1..500})BBBB"
curl -X POST -d "$PAYLOAD" "$TARGET"
Protection from this CVE:
Since the D-Link DIR-513 is end-of-life and will not receive a security patch, the only effective protection is to physically disconnect or decommission the device immediately. As a workaround, if the router must be used, it should be placed behind a firewall with strict access controls to block external access to the web administration interface, although this does not mitigate attacks from within the local network.
Impact:
Successful exploitation of this vulnerability allows an unauthenticated, remote attacker to execute arbitrary code with root privileges on the router. This could lead to a full device compromise, enabling the attacker to monitor network traffic, launch further attacks on internal systems, add the device to a botnet, or render the router inoperable (denial of service).
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Sources:
Reported By: nvd.nist.gov
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