CVE-2026-27512 in Tenda
Summary
by MITRE • 02/23/2026
Shenzhen Tenda F3 Wireless Router firmware V12.01.01.55_multi contains a content-type confusion vulnerability in the administrative interface. Responses omit the X-Content-Type-Options: nosniff header and include attacker-influenced content that can be reflected into the response body. Under affected browser behaviors, MIME sniffing may cause the response to be interpreted as active HTML, enabling script execution in the context of the administrative interface.
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Analysis
by VulDB Data Team • 02/23/2026
The vulnerability identified as CVE-2026-27512 affects the Shenzhen Tenda F3 Wireless Router firmware version 12.01.01.55_multi and represents a critical content-type confusion issue within the administrative web interface. This flaw stems from the absence of the X-Content-Type-Options: nosniff header in HTTP responses, which is a fundamental security measure designed to prevent browsers from performing MIME type sniffing on content that is explicitly declared with a specific content type. The vulnerability manifests when attacker-influenced content is reflected into the response body, creating a scenario where the web application fails to properly enforce content type boundaries and allows potentially malicious data to be interpreted by the browser in unintended ways.
The technical exploitation of this vulnerability relies on the browser's MIME sniffing behavior, which is a security mechanism that attempts to determine the correct content type of a resource when the server fails to provide an explicit content type or when the provided type is ambiguous. In affected browser environments, the lack of the X-Content-Type-Options: nosniff header means that browsers may perform aggressive content type detection and interpretation, potentially treating reflected attacker-controlled content as executable HTML even when it was originally intended to be treated as a different content type. This creates a dangerous condition where script execution can occur within the context of the administrative interface, effectively allowing an attacker to execute arbitrary code with the privileges and permissions of the administrative user.
The operational impact of this vulnerability is severe as it directly compromises the security of the router's administrative interface, which is typically protected by authentication mechanisms and serves as the primary point of access for configuring network settings, managing user accounts, and controlling network traffic. An attacker who successfully exploits this vulnerability could gain full administrative control over the router, potentially leading to complete network compromise, data interception, unauthorized access to connected devices, and the ability to redirect network traffic through malicious proxies or attack vectors. This risk is particularly concerning given that the administrative interface is often accessible from within the local network and may be protected by weak default credentials or simple authentication mechanisms.
The vulnerability aligns with CWE-16, which describes "Improper Neutralization of Special Elements used in a Web Page' and specifically addresses issues related to content type confusion and MIME sniffing. From an ATT&CK perspective, this vulnerability maps to T1059.007 for script execution and T1071.004 for application layer protocol usage, as it enables attackers to execute malicious scripts within the context of the administrative interface. The exploitation chain typically involves crafting malicious payloads that are reflected through the administrative interface and then leveraging browser MIME sniffing behavior to execute these payloads as HTML content, effectively bypassing traditional security controls that might be in place to prevent cross-site scripting attacks.
Mitigation strategies should focus on implementing the X-Content-Type-Options: nosniff header across all responses from the administrative interface, ensuring that browsers do not perform MIME type sniffing and instead respect the declared content types. Additionally, comprehensive input validation and output encoding should be implemented to prevent reflective content injection, while regular firmware updates and security patches should be deployed to address similar vulnerabilities. Network segmentation and access controls should be enforced to limit exposure of the administrative interface to trusted networks only, and multi-factor authentication should be implemented where possible to add additional layers of security. Organizations should also conduct regular security assessments of network devices and maintain up-to-date inventory of all connected devices to ensure timely patch management and vulnerability remediation.