CVE-2025-9014 in TL-WR841N v14
Summary
by MITRE • 01/15/2026
A Null Pointer Dereference vulnerability exists in the referer header check of the web portal of TP-Link TL-WR841N v14, caused by improper input validation. A remote, unauthenticated attacker can exploit this flaw and cause Denial of Service on the web portal service.This issue affects TL-WR841N v14: before 250908.
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Analysis
by VulDB Data Team • 01/31/2026
The CVE-2025-9014 vulnerability represents a critical null pointer dereference flaw within the web portal interface of TP-Link TL-WR841N v14 routers, specifically impacting firmware versions prior to 250908. This vulnerability resides in the referer header validation mechanism, which serves as a fundamental security control for web applications. The issue manifests when the router's web interface processes incoming HTTP requests and fails to properly validate the referer header parameter, creating an exploitable condition that can be leveraged by remote attackers without authentication requirements. The vulnerability's classification as a null pointer dereference aligns with CWE-476, which specifically addresses the dereferencing of null pointers in software applications.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious HTTP request containing a malformed or absent referer header value that triggers the router's web portal to attempt to dereference a null pointer during the validation process. This condition results in an immediate application crash and subsequent denial of service for the web portal service, effectively rendering the router's administrative interface inaccessible to legitimate users. The flaw demonstrates a classic input validation error where the application assumes the referer header will always contain valid data, failing to implement proper null checks or fallback mechanisms before attempting to process the header value. The vulnerability's impact extends beyond simple service disruption as it represents a fundamental weakness in the router's security architecture that could potentially be leveraged as a stepping stone for more sophisticated attacks.
From an operational perspective, this vulnerability poses significant risks to network administrators and end users who rely on the TP-Link TL-WR841N v14 for network management and configuration. The denial of service condition affects the availability of the web portal service, which is the primary interface for configuring router settings, monitoring network traffic, and managing security policies. Attackers can exploit this vulnerability to disrupt network operations, potentially causing extended downtime for small office or home networks. The vulnerability's remote and unauthenticated nature makes it particularly dangerous as it allows attackers to cause service disruption from outside the network perimeter without requiring any credentials or prior access. This characteristic aligns with ATT&CK technique T1499.004, which covers network denial of service attacks that target web services and applications.
The remediation strategy for CVE-2025-9014 requires immediate firmware updates from TP-Link to address the null pointer dereference vulnerability in the referer header validation logic. Network administrators should prioritize updating affected devices to firmware version 250908 or later, which contains the necessary patches to prevent the exploitation of this vulnerability. Additionally, implementing network segmentation and access controls can help limit the potential impact of such attacks by restricting direct access to router administrative interfaces from untrusted networks. Security monitoring should include detection of unusual traffic patterns that might indicate exploitation attempts, particularly focusing on malformed HTTP requests targeting the router's web portal. Organizations should also consider implementing network intrusion detection systems that can identify and alert on suspicious referer header values that may indicate attempts to exploit this vulnerability. The vulnerability serves as a reminder of the critical importance of proper input validation and error handling in embedded web applications, particularly those serving as network management interfaces for critical infrastructure devices.