CVE-2025-6899 Overview
CVE-2025-6899 is an operating system command injection vulnerability affecting D-Link DI-7300G+ and DI-8200G routers running firmware versions 17.12.20A1 and 19.12.25A1. The flaw resides in the msp_info.htm component, where attacker-controlled input passed to the flag, cmd, and iface arguments is incorporated into shell command execution without proper sanitization. An authenticated remote attacker can issue crafted HTTP requests to execute arbitrary OS commands on the device. The exploit details have been publicly disclosed, increasing the risk of opportunistic attacks against exposed devices. The vulnerability is tracked as CWE-77: Improper Neutralization of Special Elements used in a Command.
Critical Impact
Remote authenticated attackers can execute arbitrary operating system commands on affected D-Link DI-7300G+ and DI-8200G routers, potentially leading to full device compromise and lateral movement within the network.
Affected Products
- D-Link DI-7300G+ firmware version 19.12.25A1
- D-Link DI-8200G firmware version 16.07.26A1
- D-Link DI-7300G+ and DI-8200G hardware platforms running affected firmware
Discovery Timeline
- 2025-06-30 - CVE-2025-6899 published to NVD
- 2026-04-29 - Last updated in NVD database
Technical Details for CVE-2025-6899
Vulnerability Analysis
The vulnerability exists in the msp_info.htm handler exposed by the web management interface of the affected D-Link routers. The handler processes the flag, cmd, and iface parameters and passes their values into a system shell context without applying input validation or escaping. Because the parameters are concatenated into command strings, an attacker can inject shell metacharacters to terminate the intended command and append arbitrary commands. Successful exploitation runs in the context of the web service process, which on consumer and small-business routers is typically the root user.
Root Cause
The root cause is improper neutralization of special elements in a command string [CWE-77]. The firmware constructs OS-level commands from user-supplied HTTP parameters without sanitizing characters such as ;, |, &, or backticks. This pattern is common in embedded web interfaces that wrap CLI utilities for diagnostics or interface inspection.
Attack Vector
The vulnerability is exploitable over the network against the device's HTTP management interface. The attacker requires low-privilege authentication, after which a single crafted HTTP request to msp_info.htm containing malicious values in the flag, cmd, or iface parameter is sufficient to trigger command execution. Devices exposing the management interface to untrusted networks are at elevated risk. Public disclosure details are available in the GitHub research document and VulDB entry #314391.
No verified proof-of-concept code is published in the enriched data for this advisory. Refer to the linked references for technical reproduction details.
Detection Methods for CVE-2025-6899
Indicators of Compromise
- HTTP requests to /msp_info.htm containing shell metacharacters such as ;, |, &, $(), or backticks in the flag, cmd, or iface parameters
- Unexpected outbound connections originating from the router management plane
- New or modified files in writable firmware paths, or unexpected processes spawned by the web server
- Authentication events from unfamiliar source IP addresses immediately preceding requests to msp_info.htm
Detection Strategies
- Inspect router web server access logs for requests targeting msp_info.htm with non-alphanumeric characters in the affected query parameters
- Deploy network IDS signatures that match command injection patterns in HTTP requests to D-Link management endpoints
- Correlate administrative login events with subsequent suspicious parameter values to identify abuse of valid credentials
Monitoring Recommendations
- Forward router syslog and HTTP access logs to a centralized SIEM for retention and correlation
- Alert on any external-source HTTP request reaching the router management interface
- Monitor for configuration changes, firmware modifications, or new user accounts on affected D-Link devices
How to Mitigate CVE-2025-6899
Immediate Actions Required
- Restrict access to the router management interface to trusted internal management VLANs only, and block WAN-side administrative access
- Rotate administrative credentials on all affected D-Link DI-7300G+ and DI-8200G devices and enforce strong, unique passwords
- Audit existing accounts and remove any unrecognized administrative users
- Review device logs and configuration for signs of prior exploitation
Patch Information
No vendor patch is referenced in the enriched advisory data at the time of publication. Consult the D-Link official website and the VulDB entry for firmware updates. Apply vendor-supplied firmware as soon as it becomes available.
Workarounds
- Disable remote (WAN) management on the affected devices until a fixed firmware version is released
- Place the device management interface behind a VPN or jump host to eliminate direct exposure
- Apply ACLs on upstream network devices to restrict HTTP/HTTPS access to the router to a small set of administrative source IP addresses
- Where feasible, replace affected models with hardware running supported and patched firmware
# Example upstream ACL restricting access to the router management interface
# Replace 192.0.2.10 with the authorized administrator workstation
access-list 110 permit tcp host 192.0.2.10 host <router-ip> eq 80
access-list 110 permit tcp host 192.0.2.10 host <router-ip> eq 443
access-list 110 deny tcp any host <router-ip> eq 80
access-list 110 deny tcp any host <router-ip> eq 443
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
