CVE-2026-107918: NETGEAR R7300 Auth Bypass Vulnerability

CVE-2026-107918 Overview

CVE-2026-107918 is an input validation vulnerability in the LAN Setup feature of the NETGEAR R7300DST router. An authenticated administrator connected to the local network can submit crafted input to perform unauthorized actions on the device. The flaw was identified through testing in a controlled research environment using a simulated version of the router's software and has not been confirmed on physical production devices. The weakness is tracked as CWE-20 (Improper Input Validation).

Critical Impact

An authenticated administrator on an adjacent network can abuse insufficient input validation in the LAN Setup feature to tamper with router configuration integrity.

Affected Products

• NETGEAR R7300DST router (simulated firmware tested)
• LAN Setup configuration feature
• Devices reachable from the local (adjacent) network

Discovery Timeline

• 2026-10-13 - CVE CVE-2026-107918 published to NVD
• 2026-10-15 - Last updated in NVD database

Technical Details for CVE-2026-107918

Vulnerability Analysis

The vulnerability resides in the LAN Setup feature of the NETGEAR R7300DST router. The feature accepts administrator-supplied configuration input without performing sufficient validation on its contents. An authenticated administrator connected to the local network can submit malformed or unexpected values to influence router state in ways not intended by the vendor.

The advisory classifies the issue under CWE-20 (Improper Input Validation). Impact is limited to integrity of the router's configuration surface; confidentiality and availability are not directly affected according to the published CVSS metrics. Exploitation requires high privileges and adjacent network access, which narrows the realistic attacker population to users already inside the LAN who hold administrator credentials.

Root Cause

The LAN Setup handler fails to enforce strict validation on parameters supplied through the administrative interface. Without canonical bounds, type checks, or allow-listed values, attacker-controlled input flows into configuration logic that assumes well-formed data.

Attack Vector

The attacker must authenticate as an administrator and reach the router over the local network segment. Once authenticated, the attacker issues crafted requests to the LAN Setup endpoint. The malformed input triggers unauthorized configuration changes on the router. Remote exploitation across the internet is not described in the advisory.

No verified proof-of-concept code is available. See the NETGEAR R7300DST Support Page for vendor technical details.

Detection Methods for CVE-2026-107918

Indicators of Compromise

• Unexpected modifications to LAN Setup parameters (IP ranges, DHCP scope, subnet mask) that do not match change-management records.
• Administrator sessions originating from unusual LAN endpoints or at atypical hours.
• Router configuration backups that diverge from the last known-good baseline.

Detection Strategies

• Compare periodic router configuration exports against a signed baseline and alert on drift in LAN Setup fields.
• Enable and forward router administrative audit logs to a central logging platform for review.
• Monitor HTTP/HTTPS requests to the router management interface for malformed parameters targeting LAN Setup endpoints.

Monitoring Recommendations

• Track all authentication events against the router web UI, including source MAC and IP.
• Alert on configuration write operations performed outside approved maintenance windows.
• Correlate administrator logins with endpoint telemetry to validate the identity of the operator.

How to Mitigate CVE-2026-107918

Immediate Actions Required

• Restrict access to the router administrative interface to a dedicated management VLAN or trusted host list.
• Rotate administrator credentials and enforce strong, unique passwords on the device.
• Disable remote management and limit LAN-side administration to known workstations.
• Review router configuration against a known-good baseline and revert unauthorized changes.

Patch Information

No vendor patch is referenced in the NVD entry at the time of publication. Monitor the NETGEAR R7300DST Support Page for firmware updates addressing this issue and apply them as soon as they become available.

Workarounds

• Segment the router management interface onto an isolated administrative network.
• Limit the number of accounts with administrator privileges on the device.
• Require multi-factor authentication on jump hosts used to reach the router UI where feasible.
• Monitor LAN Setup configuration state and alert on unauthorized change events.

# Example: restrict router management access at an upstream firewall
# Allow only the trusted admin workstation to reach the router web UI
iptables -A FORWARD -s 192.0.2.25 -d 192.168.1.1 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP