CVE-2024-9911: D-Link DIR-619L Buffer Overflow Vulnerability

CVE-2024-9911 Overview

CVE-2024-9911 is a buffer overflow vulnerability in the D-Link DIR-619L B1 router running firmware version 2.06. The flaw exists in the formSetPortTr function within the /goform/formSetPortTr endpoint. Attackers can trigger the overflow by manipulating the curTime argument during an HTTP request to the router's web management interface. The vulnerability is exploitable remotely and requires low privileges. Public disclosure of the exploit technique has occurred, increasing the risk to exposed devices. The weakness is categorized under CWE-120: Buffer Copy without Checking Size of Input.

Critical Impact
Remote attackers with low privileges can trigger a buffer overflow in the router's web management interface, potentially leading to arbitrary code execution or denial of service on the affected device.

Affected Products

D-Link DIR-619L B1 hardware revision
D-Link DIR-619L Firmware version 2.06b1
End-of-life D-Link SOHO router product line

Discovery Timeline

2024-10-13 - CVE-2024-9911 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-9911

Vulnerability Analysis

The vulnerability resides in the formSetPortTr handler, which processes port trigger configuration requests submitted to /goform/formSetPortTr. The handler reads the curTime request parameter and copies it into a fixed-size stack or heap buffer without validating the input length. Supplying an oversized curTime value overruns the buffer boundary and corrupts adjacent memory.

On embedded MIPS or ARM targets like the DIR-619L, this class of overflow typically overwrites saved return addresses or function pointers on the stack. Successful corruption enables control-flow hijacking, which attackers can leverage to execute arbitrary code with the privileges of the web server process, commonly root on consumer routers.

The D-Link DIR-619L is an end-of-life product. The vendor has confirmed it will not receive security patches, which leaves affected units permanently vulnerable to this and related flaws.

Root Cause

The root cause is missing input length validation on the curTime parameter before it is copied into a fixed-size buffer. The formSetPortTr function uses an unsafe string copy operation that does not enforce boundary checks, satisfying the classic conditions for a stack or heap buffer overflow described in CWE-120.

Attack Vector

An authenticated attacker with low-privilege access to the router's web administration interface sends a crafted HTTP POST request to /goform/formSetPortTr containing an overlong curTime value. Because the attack originates over the network with low complexity, any exposed management interface, including those inadvertently reachable from the WAN, is at risk. Refer to the public vulnerability write-up on GitHub for the technical proof-of-concept.

The vulnerability manifests when the formSetPortTr handler copies
the attacker-controlled curTime HTTP parameter into a fixed-size buffer
without length validation. No verified public exploit code is reproduced here.
See the referenced GitHub advisory for technical proof-of-concept details.

Detection Methods for CVE-2024-9911

Indicators of Compromise

HTTP POST requests to /goform/formSetPortTr containing abnormally long curTime parameter values.
Unexpected reboots, web interface crashes, or httpd process restarts on DIR-619L routers.
Outbound connections from the router to unknown hosts, suggesting successful code execution.

Detection Strategies

Inspect HTTP traffic destined for router management interfaces and flag requests to /goform/formSetPortTr with curTime values exceeding expected length limits.
Correlate router syslog entries for repeated authentication events followed by process crashes on the web server.
Deploy network intrusion detection signatures that match the exploit pattern published in the GitHub advisory.

Monitoring Recommendations

Monitor DHCP and ARP tables for D-Link DIR-619L devices in the environment and flag them for replacement.
Alert on any external access to router administration ports (80/tcp, 443/tcp, 8080/tcp).
Log and review all configuration changes to port triggering rules on SOHO routers.

How to Mitigate CVE-2024-9911

Immediate Actions Required

Disable remote (WAN-side) management on all DIR-619L devices and restrict administrative access to trusted LAN hosts only.
Replace the DIR-619L with a currently supported router model, since the device is end-of-life and no patch will be released.
Rotate the router administrator credentials to reduce the risk of low-privilege exploitation.

Patch Information

D-Link has designated the DIR-619L as an end-of-life and end-of-support product. No firmware update addressing CVE-2024-9911 is available. Consult the D-Link official website and the VulDB entry for the vendor's current support status and migration guidance.

Workarounds

Segment vulnerable routers onto isolated network segments with no reachability to sensitive internal assets.
Block inbound connections to the router's HTTP administration interface at the perimeter firewall.
Disable the port triggering feature if not required to reduce exposure to the formSetPortTr handler.

bash

# Example: block WAN access to router management interface via upstream firewall
iptables -A FORWARD -p tcp --dport 80 -d <router_wan_ip> -j DROP
iptables -A FORWARD -p tcp --dport 443 -d <router_wan_ip> -j DROP