CVE-2026-75753 in ASUS
Summary
by MITRE • 10/20/2026
Missing Authentication for a Critical Function in certain ASUS routers allows an unauthorized nearby user to send specific commands via HTTP requests, causing the router to return device identification information and switch into a specific mode. As a result, when the router encounters abnormal conditions, it may be unable to perform self-recovery. Refer to the ' Security Update for ASUS Router Firmware' section on the ASUS Security Advisory for more information.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified in certain ASUS routers represents a critical failure in access control mechanisms, specifically categorized under CWE-306 as Missing Authentication for Critical Function. This flaw allows an attacker who is physically nearby or has network connectivity to the device to interact with sensitive administrative interfaces without providing valid credentials. The core technical issue lies in the router's HTTP server implementation, which fails to enforce authentication checks on specific endpoints designed for diagnostic or maintenance purposes. By sending crafted HTTP requests to these unprotected paths, an unauthorized user can trigger internal processes that are intended only for authenticated administrators or factory reset procedures. This lack of verification bypasses the primary defense layer of the device, granting remote actors direct control over critical system states and information retrieval mechanisms.
The operational impact of this vulnerability is twofold, involving both data exposure and service disruption. First, the attacker can extract sensitive device identification information, such as serial numbers, MAC addresses, and potentially other unique identifiers that could be used for targeted attacks or inventory tracking within a network environment. Second, and more critically, the ability to force the router into specific modes via HTTP requests can lead to severe availability issues. When the router is placed in these unintended states, it may become unable to perform self-recovery mechanisms during abnormal conditions. This means that if the device encounters a fault or requires a reboot, it might remain stuck in the compromised state rather than returning to normal operation, effectively resulting in a denial of service for connected devices and users on the local network.
From an offensive security perspective, this vulnerability aligns with ATT&CK technique T1078, specifically Valid Accounts, although in this case, no valid account is required due to the missing authentication check. It also relates to T1499, Endpoint Denial of Service, as the ability to lock the device into a non-recoverable mode disrupts normal operations. The attack vector typically involves local network access or potentially remote exploitation if the affected HTTP service is exposed to untrusted networks without proper firewalling. This highlights a significant gap in the security design philosophy where convenience features like quick diagnostic tools are prioritized over strict authentication boundaries, creating an easy entry point for malicious actors within physical proximity of the target device.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary solution is to apply the firmware updates provided by ASUS as detailed in their security advisory, which patch the specific HTTP endpoints responsible for this behavior. Administrators should ensure that all connected devices are running the latest stable firmware versions to close these authentication gaps. Additionally, network segmentation can help limit exposure; placing routers behind robust firewalls and restricting management interfaces to trusted IP ranges reduces the attack surface available to nearby attackers. Future development cycles should enforce strict principle of least privilege for all administrative functions, ensuring that any command capable of altering device state or exposing sensitive data requires multi-factor authentication or at minimum strong single-sign-on verification before execution.