CVE-2026-107917: NETGEAR R7300 Auth Bypass Vulnerability

CVE-2026-107917 Overview

CVE-2026-107917 is an input validation vulnerability [CWE-20] in the PPPoE Setup feature of the NETGEAR R7300 router. The flaw allows an authenticated administrator connected to the local network to perform unauthorized actions against the router. The issue was identified in a controlled research environment using a simulated version of the router's software and has not been confirmed on physical production devices. Exploitation requires administrative credentials and adjacent network access, limiting the practical attack surface. The vulnerability affects the integrity of router configuration but does not directly impact confidentiality or availability according to the published scoring.

Critical Impact
An authenticated administrator on the local network can leverage insufficient input validation in the PPPoE Setup feature to modify router behavior in unauthorized ways.

Affected Products

NETGEAR R7300 router (also referenced as R7300DST)
PPPoE Setup feature within the router administrative interface
Simulated firmware image used for controlled testing (physical device impact unconfirmed)

Discovery Timeline

2026-10-13 - CVE-2026-107917 published to the National Vulnerability Database
2026-10-15 - Last updated in NVD database

Technical Details for CVE-2026-107917

Vulnerability Analysis

The vulnerability resides in the PPPoE Setup handler of the NETGEAR R7300 web management interface. The handler accepts configuration input from an authenticated administrator but does not sufficiently validate or sanitize the supplied values before processing. An attacker with administrative credentials on the adjacent local network can submit crafted input that the router processes as legitimate configuration data. The result is unauthorized modification of router state through a path that should enforce stricter input constraints. The vendor advisory notes the finding was reproduced in a simulated firmware environment and has not been validated on production hardware, which affects the real-world exploitability assessment.

Root Cause

The root cause is improper input validation [CWE-20] within the PPPoE Setup processing logic. The feature trusts that administrative input conforms to expected format and content without enforcing those assumptions programmatically. Missing boundary checks and format validation allow values outside the intended specification to reach downstream configuration routines.

Attack Vector

Exploitation requires three preconditions. The attacker must hold valid administrator credentials, must be connected to the same local or adjacent network as the router, and must reach the web management interface. The attacker then submits malformed input through the PPPoE Setup form or its underlying endpoint to trigger the unauthorized action. Because authentication and adjacency are required, remote internet-based exploitation is not in scope for this issue.

The vulnerability manifests in the PPPoE configuration handler. No verified proof-of-concept code is published. Refer to the NETGEAR R7300DST Support Page for vendor technical details.

Detection Methods for CVE-2026-107917

Indicators of Compromise

Unexpected changes to PPPoE configuration parameters on the R7300 router
Administrative logins from local network hosts that do not correspond to known administrators
Router behavior changes, such as altered WAN connectivity or unexpected authentication prompts, following administrative sessions

Detection Strategies

Review router administration logs for PPPoE Setup submissions outside of planned change windows
Compare current router configuration against a known-good baseline to identify unauthorized modifications
Monitor local network traffic to the router management interface for abnormal POST request patterns targeting PPPoE endpoints

Monitoring Recommendations

Enable syslog forwarding from the router to a centralized log collector for persistent retention and search
Alert on administrative authentication events originating from unexpected MAC addresses or VLAN segments
Track configuration drift on edge routers using periodic configuration pulls and diff comparisons

How to Mitigate CVE-2026-107917

Immediate Actions Required

Restrict access to the router administrative interface to a dedicated management VLAN or trusted host list
Rotate the router administrator password and ensure it meets strong complexity requirements
Disable remote management if it is not required for operations
Audit all accounts with administrative privileges on the device and remove unused credentials

Patch Information

No vendor patch is referenced in the published CVE record. Monitor the NETGEAR R7300DST Support Page for firmware updates addressing this issue and apply them when available.

Workarounds

Segment the router management interface onto a restricted network accessible only to authorized administrators
Avoid configuring PPPoE parameters from untrusted or shared workstations
Limit the number of accounts with administrative privileges on the device
Monitor router configuration for unauthorized changes until a firmware fix is available

bash

# Example: restrict management access with host-based ACL on upstream switch
# Replace interface and address with values matching your environment
access-list 10 permit host 192.0.2.25
access-list 10 deny any log
interface vlan 10
 ip access-group 10 in