CVE-2025-11100 Overview
CVE-2025-11100 is a command injection vulnerability affecting the D-Link DIR-823X router running firmware version 250416. The flaw resides in the uci_set function handling requests to /goform/set_wifi_blacklists. Attackers can manipulate request parameters to inject operating system commands processed by the router. The attack is exploitable remotely over the network and requires low-level privileges. Public exploit details have been disclosed, increasing the likelihood of opportunistic abuse against exposed devices. The vulnerability is classified under CWE-74, Improper Neutralization of Special Elements in Output Used by a Downstream Component.
Critical Impact
Authenticated remote attackers can inject arbitrary commands into the router's underlying OS through the Wi-Fi blacklist configuration endpoint, with public exploit details available.
Affected Products
- D-Link DIR-823X router (hardware)
- D-Link DIR-823X firmware version 250416
- Deployments exposing the web administration interface
Discovery Timeline
- 2025-09-28 - CVE-2025-11100 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-11100
Vulnerability Analysis
The DIR-823X firmware exposes a web administration endpoint at /goform/set_wifi_blacklists. This endpoint processes blacklist parameters and forwards them to the internal uci_set function, which writes configuration values to the Unified Configuration Interface (UCI) backend. The function fails to neutralize shell metacharacters supplied through user-controllable fields. As a result, crafted input is concatenated into a shell command and executed by the router's underlying Linux system. Public technical documentation describing the affected code path is available in the GitHub Configuration Documentation and the VulDB #326181 entry. The vulnerability is tracked under EPSS at 4.125% probability, placing it in the 89.49 percentile for relative exploitation likelihood.
Root Cause
The root cause is improper neutralization of special characters before passing user-supplied data to a downstream interpreter, consistent with [CWE-74]. The uci_set handler concatenates request parameters directly into command strings rather than using safe argument arrays or parameterized APIs.
Attack Vector
The attack vector is network-based against the router's HTTP administrative service. An authenticated attacker with low privileges sends a crafted POST request to /goform/set_wifi_blacklists containing shell metacharacters in a blacklist field. The uci_set routine executes the injected command in the context of the web server process, which typically runs with elevated privileges on consumer routers.
No verified proof-of-concept code is published in this article. Refer to the GitHub Configuration Documentation for the technical write-up of the affected function.
Detection Methods for CVE-2025-11100
Indicators of Compromise
- Unexpected HTTP POST requests to /goform/set_wifi_blacklists containing shell metacharacters such as ;, |, `, $(, or && in parameter values.
- New or unauthorized accounts, cron entries, or persistent processes on the router shell environment.
- Outbound connections from the router to unknown hosts on non-standard ports following administrative requests.
Detection Strategies
- Inspect router access logs and any upstream web application firewall logs for requests targeting /goform/set_wifi_blacklists with suspicious characters.
- Correlate authentication events on the router with subsequent configuration changes to identify abuse of low-privileged accounts.
- Apply network intrusion detection signatures that match command injection patterns in HTTP request bodies destined for DIR-823X management interfaces.
Monitoring Recommendations
- Restrict and monitor management plane access to the router; alert on any administrative session originating from untrusted network segments.
- Capture and review firmware-level syslog output where supported, focusing on shell invocations spawned by the web service.
- Track DNS and NetFlow telemetry from router IP addresses for anomalous egress that may indicate post-exploitation activity.
How to Mitigate CVE-2025-11100
Immediate Actions Required
- Block remote (WAN-side) access to the DIR-823X web administration interface and restrict LAN access to trusted hosts only.
- Rotate all administrative credentials and disable unused administrative accounts that could be leveraged for the authenticated request.
- Audit the device for unauthorized configuration changes, persistence mechanisms, and unknown processes.
Patch Information
At the time of publication, no vendor advisory or fixed firmware release is referenced in the available data. Monitor the D-Link Official Website and VulDB #326181 for updates. Apply any subsequent firmware release from D-Link that addresses the uci_set handler in /goform/set_wifi_blacklists.
Workarounds
- Disable remote management features and confirm the administrative interface is unreachable from the internet.
- Place the router behind a segmented management VLAN with access control lists limiting which clients can reach the web UI.
- Replace affected devices with a supported model if a vendor patch is unavailable for an extended period.
# Example: block external access to the router web UI from upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_interface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_interface> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
