CVE-2025-2619: D-Link DAP-1620 Buffer Overflow Flaw

CVE-2025-2619 Overview

A critical stack-based buffer overflow vulnerability has been identified in the D-Link DAP-1620 wireless range extender firmware version 1.03. The vulnerability exists in the check_dws_cookie function within the /storage component's Cookie Handler. This flaw allows remote attackers to exploit the device over the network without requiring authentication, potentially leading to complete device compromise.

Critical Impact
This vulnerability enables remote attackers to execute arbitrary code with elevated privileges on affected D-Link DAP-1620 devices. The device is no longer supported by D-Link, meaning no official patches will be released.

Affected Products

D-Link DAP-1620 Firmware version 1.03
D-Link DAP-1620 Hardware (all revisions running vulnerable firmware)

Discovery Timeline

2025-03-22 - CVE-2025-2619 published to NVD
2025-03-26 - Last updated in NVD database

Technical Details for CVE-2025-2619

Vulnerability Analysis

This vulnerability is a stack-based buffer overflow (CWE-787: Out-of-bounds Write, CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) affecting the cookie handling mechanism in the D-Link DAP-1620 firmware. The check_dws_cookie function fails to properly validate the size of input data before copying it to a fixed-size stack buffer, allowing attackers to overwrite adjacent memory regions including the return address.

The vulnerability is particularly dangerous because it can be triggered remotely over the network without any form of authentication or user interaction. An attacker can craft malicious HTTP requests with specially formed cookie values that exceed the expected buffer size, triggering the overflow condition.

Root Cause

The root cause of this vulnerability lies in insufficient bounds checking within the check_dws_cookie function located in the /storage component. When processing incoming HTTP cookie data, the function copies user-supplied input into a stack-allocated buffer without verifying that the input length does not exceed the buffer's capacity. This classic memory safety issue allows attackers to corrupt stack memory and potentially hijack program execution flow.

Attack Vector

The attack vector for CVE-2025-2619 is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by sending specially crafted HTTP requests to the device's web interface containing malicious cookie data. The vulnerable Cookie Handler processes this data through the check_dws_cookie function, where the oversized input triggers the buffer overflow.

Successful exploitation could allow an attacker to achieve remote code execution on the device with the privileges of the web server process, typically running as root on embedded devices. This could lead to complete device takeover, network traffic interception, or use of the device as a pivot point for further attacks on the internal network.

The vulnerability has been publicly disclosed and technical details are available through security research publications, increasing the risk of exploitation attempts.

Detection Methods for CVE-2025-2619

Indicators of Compromise

Unusual HTTP requests targeting the /storage endpoint with abnormally large cookie values
Unexpected device reboots or crashes indicating potential exploitation attempts
Anomalous outbound network connections from the DAP-1620 device
Modified device configuration or unexpected firmware changes

Detection Strategies

Monitor network traffic for HTTP requests to D-Link DAP-1620 devices with oversized cookie headers
Implement intrusion detection rules to identify buffer overflow attack patterns against embedded web servers
Deploy network segmentation to isolate IoT devices and monitor cross-segment traffic for anomalies
Review web server logs on the device (if accessible) for malformed cookie-related errors

Monitoring Recommendations

Implement network-level monitoring for all traffic to and from D-Link DAP-1620 devices
Configure alerts for unusual HTTP traffic patterns targeting the /storage endpoint
Monitor for signs of device compromise such as unexpected configuration changes or new network connections
Conduct regular vulnerability scans of network infrastructure to identify unpatched or end-of-life devices

How to Mitigate CVE-2025-2619

Immediate Actions Required

Immediately isolate affected D-Link DAP-1620 devices from untrusted networks and the internet
Disable remote management interfaces if enabled on the device
Consider replacing the device with a currently supported alternative, as D-Link no longer provides security updates for this model
Implement network segmentation to limit exposure of the vulnerable device

Patch Information

No official patch is available for this vulnerability. D-Link has confirmed that the DAP-1620 has reached end-of-life status and is no longer supported with security updates. Users are strongly advised to replace affected devices with currently supported hardware.

For more information, refer to the D-Link Official Website and the vulnerability details on VulDB.

Workarounds

Place the D-Link DAP-1620 behind a firewall that blocks external access to the device's web interface
Disable the web administration interface if the device supports command-line or other non-HTTP management methods
Implement strict network access controls to limit which hosts can communicate with the device
Monitor the device for signs of compromise and be prepared for immediate replacement if exploitation is suspected

bash

# Network isolation example using iptables (on gateway/firewall)
# Block external access to DAP-1620 device web interface
iptables -A FORWARD -d <DAP-1620-IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <DAP-1620-IP> -p tcp --dport 443 -j DROP

# Allow only trusted management hosts
iptables -I FORWARD -s <TRUSTED-ADMIN-IP> -d <DAP-1620-IP> -p tcp --dport 80 -j ACCEPT