CVE-2026-11733: NETGEAR Buffer Overflow Vulnerability

CVE-2026-11733 Overview

CVE-2026-11733 is a stack-based buffer overflow vulnerability [CWE-121] affecting multiple NETGEAR router models. An authenticated device administrator on an adjacent network can trigger the flaw to temporarily interrupt normal device operation. The vulnerability results in a denial of service (DoS) condition rather than code execution or data compromise. NETGEAR published the issue in the August 2026 security advisory covering the RAX41, RAX41v2, RAX42, RAX42v2, RAX43, RAX43v2, RAX49s, RAX50, and RAX50v2 product lines.

Critical Impact
An authenticated administrator with adjacent network access can trigger a buffer overflow that temporarily disrupts router availability, interrupting connectivity for downstream clients.

Affected Products

NETGEAR RAX41 and RAX41v2 routers
NETGEAR RAX42, RAX42v2, RAX43, and RAX43v2 routers
NETGEAR RAX49s, RAX50, and RAX50v2 routers

Discovery Timeline

2026-08-11 - CVE-2026-11733 published to the National Vulnerability Database
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-11733

Vulnerability Analysis

The flaw is a stack-based buffer overflow [CWE-121] in firmware running on the affected NETGEAR RAX-series Wi-Fi routers. Exploitation requires an authenticated administrator on an adjacent network segment, which substantially narrows the attacker population. Successful triggering causes a temporary interruption to normal device operation, consistent with a denial of service outcome. The vulnerability does not expose confidentiality or integrity impacts based on the published advisory. Recovery from the condition is not automatic and may require user intervention to restore service.

Root Cause

The root cause is improper bounds checking on data written to a fixed-size stack buffer within the router firmware. When input length exceeds the allocated buffer, adjacent stack memory is corrupted and the affected process terminates or hangs. NETGEAR has not publicly detailed the specific service, parameter, or firmware component involved.

Attack Vector

Exploitation requires adjacent network access, such as a connection to the router's LAN or Wi-Fi segment, combined with valid administrator credentials. A remote attacker on the internet cannot reach the vulnerable code path directly. The attacker submits an overlong input to an administrative interface, corrupting the stack and interrupting router operation. See the NETGEAR Security Advisory for vendor-provided details.

Detection Methods for CVE-2026-11733

Indicators of Compromise

Unexpected reboots, service hangs, or interface unavailability on RAX-series routers following administrative activity
Loss of client connectivity coinciding with authenticated admin sessions from adjacent network hosts
Router system logs showing crashes, watchdog resets, or process termination during configuration operations

Detection Strategies

Correlate administrator authentication events on the router with subsequent availability failures or reboots
Monitor syslog output from NETGEAR devices for crash signatures, kernel panics, or repeated daemon restarts
Review administrative account activity for logins originating from unexpected LAN or Wi-Fi endpoints

Monitoring Recommendations

Forward router syslog to a centralized logging platform and alert on availability disruptions tied to admin sessions
Track and inventory all accounts with administrative privileges on affected NETGEAR models
Baseline normal admin activity patterns and flag anomalous configuration requests or oversized parameters

How to Mitigate CVE-2026-11733

Immediate Actions Required

Apply the firmware updates referenced in the August 2026 NETGEAR Security Advisory for all affected RAX models
Rotate router administrator credentials and enforce strong, unique passwords for each device
Restrict administrative access to trusted management VLANs or specific host addresses
Disable remote management if not required for operational purposes

Patch Information

NETGEAR published fixed firmware for the affected RAX-series products in the August 2026 security advisory. Refer to the individual product support pages for download links: RAX41, RAX41v2, RAX42, RAX42v2, RAX43, RAX43v2, RAX49s, RAX50, and RAX50v2.

Workarounds

Segment router management interfaces onto a dedicated administrative network isolated from general user traffic
Limit administrative accounts to the minimum number of personnel who require them
Monitor router availability and log admin session activity until firmware updates can be deployed

bash

# Configuration example
# Restrict router admin access to a specific management host on the LAN
# (Apply through the router web UI: Advanced > Administration > Remote Management)
# 1. Disable Remote Management from WAN
# 2. Set LAN admin access allow-list to trusted management workstation IP
# 3. Change default admin password and enable session timeout