CVE-2025-6115 Overview
CVE-2025-6115 is a stack-based buffer overflow vulnerability in the D-Link DIR-619L router running firmware version 2.06B01. The flaw resides in the form_macfilter function, where the mac_hostname_%d and sched_name_%d arguments are copied without bounds checking. Remote attackers with low-privileged access can trigger the overflow over the network to corrupt the stack and potentially execute arbitrary code. The exploit details have been disclosed publicly through VulDB and a GitHub proof-of-concept. The D-Link DIR-619L has reached end-of-life status, and the vendor will not issue a patch for affected devices.
Critical Impact
Remote attackers can trigger a stack-based buffer overflow in form_macfilter to corrupt memory and potentially execute arbitrary code on unsupported D-Link DIR-619L routers.
Affected Products
- D-Link DIR-619L hardware (end-of-life)
- D-Link DIR-619L firmware version 2.06B01
- Any deployment exposing the router web management interface to untrusted networks
Discovery Timeline
- 2025-06-16 - CVE-2025-6115 published to NVD
- 2025-06-17 - Last updated in NVD database
Technical Details for CVE-2025-6115
Vulnerability Analysis
The vulnerability lives in the form_macfilter handler that processes MAC address filtering submissions from the router's web administration interface. Attacker-controlled parameters named mac_hostname_%d and sched_name_%d are copied into fixed-size stack buffers without length validation. Submitting oversized values overruns the buffer and overwrites adjacent stack memory, including saved return addresses. The weakness is classified under [CWE-119], improper restriction of operations within the bounds of a memory buffer. Because the DIR-619L runs on MIPS architecture with limited memory protections, successful corruption can redirect execution flow to attacker-supplied code.
Root Cause
The form_macfilter function relies on unsafe string copy operations against user-supplied form fields. The firmware lacks bounds checking on the mac_hostname_%d and sched_name_%d parameters before writing them to stack-allocated buffers. Combined with the absence of stack canaries and address space layout randomization in this embedded firmware build, the overflow becomes directly exploitable.
Attack Vector
An attacker sends a crafted HTTP POST request to the MAC filter configuration endpoint of the router web interface. The request supplies oversized values in the vulnerable hostname or schedule name fields. Exploitation requires network reachability to the management interface and low-privileged authentication. A public proof-of-concept is documented in the GitHub PoC Repository and tracked in VulDB #312584.
No verified exploit code is reproduced here. Refer to the linked proof-of-concept for the request structure and parameter layout used to trigger the overflow.
Detection Methods for CVE-2025-6115
Indicators of Compromise
- HTTP POST requests to the router administration interface containing abnormally long mac_hostname_* or sched_name_* parameter values
- Unexpected reboots, crashes, or process restarts on DIR-619L devices following inbound web management traffic
- New or modified MAC filter rules that the administrator did not configure
- Outbound connections from the router to unknown external hosts after web interface activity
Detection Strategies
- Inspect web server logs on the router or upstream proxy for requests to the MAC filter endpoint with parameter values exceeding expected hostname or schedule name lengths
- Deploy network intrusion detection signatures that flag HTTP requests carrying oversized form fields targeting D-Link administrative paths
- Monitor SNMP or syslog output from the router for crash, watchdog reset, or memory fault messages
Monitoring Recommendations
- Forward router logs to a centralized log platform and alert on repeated 5xx responses or service restarts on the administrative interface
- Track inbound connections to TCP/80 and TCP/443 on router management addresses, alerting on access from non-administrative source ranges
- Audit MAC filter configuration state on a scheduled basis to identify unauthorized modifications
How to Mitigate CVE-2025-6115
Immediate Actions Required
- Restrict access to the router web administration interface to trusted management VLANs or specific administrative hosts
- Disable remote management features on the WAN side of the DIR-619L
- Replace the DIR-619L with a vendor-supported router model, as the device is end-of-life and will not receive a fix
- Rotate administrative credentials to limit the risk of low-privileged attacker access required for exploitation
Patch Information
No patch is available. D-Link has confirmed that the DIR-619L is no longer supported, and the vendor will not release firmware updates addressing CVE-2025-6115. The only durable remediation is hardware replacement. See the D-Link Official Site for current supported product lines.
Workarounds
- Place the router behind a network segment that blocks untrusted access to the administrative interface
- Enforce strong administrative passwords and disable any default or guest accounts on the device
- Use an upstream firewall to filter HTTP and HTTPS traffic destined for the router management ports
- Decommission the device from production networks if replacement is not immediately feasible
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
