CVE-2024-9786 Overview
CVE-2024-9786 is a buffer overflow vulnerability in the D-Link DIR-619L B1 router running firmware version 2.06. The flaw resides in the formSetLog function within /goform/formSetLog, where the curTime argument is processed without adequate bounds checking. Attackers can trigger the overflow remotely across the network, and a public exploit has been disclosed. The DIR-619L B1 is a legacy consumer router, and D-Link has not published a vendor advisory for this issue within the referenced sources.
Critical Impact
Remote attackers can corrupt memory on affected DIR-619L B1 routers by manipulating the curTime parameter, enabling potential code execution and full device compromise.
Affected Products
- D-Link DIR-619L B1 hardware revision
- D-Link DIR-619L Firmware version 2.06b1
- Deployments exposing the web management interface (/goform/formSetLog)
Discovery Timeline
- 2024-10-10 - CVE-2024-9786 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-9786
Vulnerability Analysis
The vulnerability exists in the formSetLog handler exposed through the router's web management interface at /goform/formSetLog. The handler accepts a curTime argument from HTTP requests and copies its value into a fixed-size buffer without validating the input length. Supplying an oversized curTime value overflows adjacent stack or heap memory, classifying the issue under [CWE-120] Buffer Copy without Checking Size of Input.
Attackers with low-privileged access to the web interface can send crafted HTTP requests over the network to trigger the overflow. Successful exploitation can lead to arbitrary code execution on the router, denial of service, or persistent implant deployment. The public disclosure of exploitation details on GitHub increases the risk of opportunistic scanning against internet-exposed DIR-619L devices.
Root Cause
The root cause is the absence of length validation on the curTime request parameter before it is passed to an unsafe copy operation inside formSetLog. Legacy MIPS-based D-Link firmware commonly uses strcpy or sprintf against webs_get_var-style helpers without bounds enforcement, which produces exploitable stack corruption on this platform.
Attack Vector
Exploitation requires network access to the router's HTTP administration interface and a set of valid low-privileged credentials. The attacker submits a POST request to /goform/formSetLog containing an overlong curTime value. On devices where the management interface is exposed to the WAN, exploitation is reachable from the internet. See the GitHub Vulnerability Report and VulDB entry #279938 for technical proof-of-concept details.
Detection Methods for CVE-2024-9786
Indicators of Compromise
- HTTP POST requests to /goform/formSetLog containing abnormally long curTime parameter values
- Router reboots, watchdog resets, or httpd process crashes following administrative HTTP traffic
- Unexpected outbound connections from the router to unknown hosts after web interface access
- New or modified firewall, DNS, or DHCP configuration on the DIR-619L that does not match change records
Detection Strategies
- Inspect network traffic for HTTP requests to formSetLog with curTime values exceeding typical timestamp lengths
- Alert on repeated authentication attempts against the DIR-619L admin interface followed by anomalous POST bodies
- Fingerprint DIR-619L B1 devices running firmware 2.06b1 on the network and flag them as end-of-life assets
Monitoring Recommendations
- Forward router syslog and web access logs to a centralized SIEM for anomaly detection
- Monitor for DNS resolution changes on client devices that could indicate router-level compromise
- Watch for scanning activity targeting /goform/ endpoints across the perimeter
How to Mitigate CVE-2024-9786
Immediate Actions Required
- Disable remote (WAN-side) administration on the DIR-619L web interface
- Restrict LAN access to the router management page to a dedicated administrative host or VLAN
- Rotate administrative credentials and enforce strong, unique passwords for the router
- Plan replacement of the DIR-619L B1, which is a legacy consumer platform, with a currently supported model
Patch Information
No vendor patch is referenced in the enriched CVE data for the DIR-619L B1 firmware 2.06b1. The DIR-619L product line is legacy, and no security update from D-Link is listed in the external references. Organizations should treat affected devices as unsupported and prioritize decommissioning.
Workarounds
- Block inbound TCP access to the router's HTTP/HTTPS management ports from untrusted networks
- Place the router behind an upstream firewall that filters requests to /goform/formSetLog
- Segment IoT and consumer-grade network equipment away from sensitive corporate assets
- Replace the DIR-619L B1 with a vendor-supported router that receives active security updates
# Example: block WAN-side access to the router web UI using an upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_iface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_iface> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
