CVE-2024-9912 Overview
CVE-2024-9912 is a buffer overflow vulnerability in the D-Link DIR-619L B1 2.06 wireless router. The flaw resides in the formSetQoS function within the /goform/formSetQoS endpoint of the device's web management interface. An attacker can trigger the overflow by manipulating the curTime argument, corrupting adjacent memory on the router. The vulnerability is exploitable remotely and requires only low privileges to initiate. Public disclosure of the exploit details has occurred, increasing the risk of opportunistic exploitation against exposed devices. The vulnerability is classified under [CWE-120] (Classic Buffer Copy Without Checking Size of Input).
Critical Impact
Remote attackers can corrupt router memory through the curTime parameter, potentially leading to arbitrary code execution or device compromise.
Affected Products
- D-Link DIR-619L Router (hardware revision B1)
- D-Link DIR-619L Firmware version 2.06B1
- Web management interface endpoint /goform/formSetQoS
Discovery Timeline
- 2024-10-13 - CVE-2024-9912 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-9912
Vulnerability Analysis
The vulnerability exists in the formSetQoS handler that processes Quality of Service (QoS) configuration requests submitted through the router's web interface. When the handler receives a POST request to /goform/formSetQoS, it reads the curTime parameter from the request body. The function copies this attacker-controlled value into a fixed-size stack buffer without validating the input length. Supplying an overly long curTime string overflows the buffer and overwrites adjacent stack memory, including saved return addresses.
D-Link DIR-619L is a consumer-grade wireless router that has reached end-of-life status. Because the affected code path is reachable from an authenticated session on the router's LAN or WAN interface (when remote management is enabled), attackers on the same network segment or across the internet can reach the vulnerable endpoint. Successful exploitation can result in denial of service or remote code execution on the MIPS-based device.
Root Cause
The root cause is missing bounds checking on the curTime HTTP parameter inside the formSetQoS function. The function uses an unsafe string copy operation to move user-supplied data into a stack-allocated buffer of fixed length. No length validation, truncation, or safe-copy primitive protects the destination buffer, matching the [CWE-120] pattern.
Attack Vector
An attacker sends a crafted HTTP POST request to /goform/formSetQoS containing an oversized curTime value. The attack requires low-level authentication on the router's management interface but no user interaction. Because many DIR-619L deployments use default credentials or expose the web UI to the WAN, the practical barrier to exploitation is low. Detailed exploitation notes are published in the GitHub Vulnerability Documentation and VulDB #280240.
No verified exploit code is reproduced here. Refer to the referenced advisory for the parameter structure and offset analysis.
Detection Methods for CVE-2024-9912
Indicators of Compromise
- Unusually long curTime values in HTTP POST bodies sent to /goform/formSetQoS.
- Router crash, reboot loops, or unexpected loss of management interface availability following inbound HTTP traffic.
- Outbound connections from the router to unknown hosts, indicating post-exploitation activity.
- Modified DNS or QoS configuration entries that do not match administrator changes.
Detection Strategies
- Inspect HTTP requests to the router management interface for curTime parameter values exceeding expected timestamp lengths.
- Deploy network IDS signatures targeting POST requests to /goform/formSetQoS with anomalous payload sizes.
- Correlate router availability events with preceding HTTP traffic to identify probing attempts.
Monitoring Recommendations
- Log all administrative access attempts to the DIR-619L web interface and forward them to a central SIEM.
- Monitor WAN-side exposure of TCP ports 80 and 443 on affected routers using external attack surface tooling.
- Alert on repeated failed authentications followed by successful login and immediate configuration changes.
How to Mitigate CVE-2024-9912
Immediate Actions Required
- Disable remote (WAN-side) management on the DIR-619L web interface to reduce internet-facing exposure.
- Restrict LAN-side access to the /goform/formSetQoS endpoint through segmentation or ACLs where possible.
- Rotate router administrator credentials and disable default accounts.
- Plan replacement of end-of-life DIR-619L hardware with a supported router platform.
Patch Information
The D-Link DIR-619L has reached end-of-support status, and no vendor patch is available for firmware version 2.06B1 addressing CVE-2024-9912. Consult the D-Link Official Website for product lifecycle information and consider migrating to a currently supported model.
Workarounds
- Place affected routers behind a network firewall that blocks unsolicited inbound HTTP traffic to the management interface.
- Enable IP-based access restrictions on the router administration page so only trusted management hosts can reach it.
- Isolate the router on a dedicated management VLAN to prevent untrusted LAN clients from reaching the vulnerable endpoint.
- Decommission the device if it exposes services to untrusted networks and a supported replacement is available.
# Example firewall rule blocking external access to router management (upstream firewall)
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -m state --state NEW -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -m state --state NEW -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
