TP-Link Router Flaws Allowed Attackers to Launch DoS Attacks and Cause Crashes

TP-Link has recently addressed a batch of severe vulnerabilities affecting the Tapo C520WS security camera system.

Security cameras are critical pieces of equipment for home and business safety, making device stability a top priority.

When vulnerabilities allow threat actors to knock these devices offline or change their settings without permission, it poses a direct risk to physical security.

Users must apply the latest firmware update to secure their networks against these high-severity risks.

CVE-2026-34118 to CVE-2026-34120: Heap-Based Buffer Overflows

Security researchers discovered three distinct heap-based buffer overflow vulnerabilities linked to how the device processes data.

These flaws happen because the system fails to properly check the size boundaries of HTTP or streaming inputs provided by external sources.

An attacker sharing the same network segment can easily exploit this by sending specially crafted payloads.

When the device receives these payloads, it writes data outside its safely allocated memory boundaries.

This triggers memory corruption, resulting in a Denial-of-Service (DoS) condition that causes the system process to crash or completely freeze up. The three specific triggers are:

• CVE-2026-34118: A flaw in the HTTP POST parsing logic caused by missing capacity checks after dynamic memory allocation.
• CVE-2026-34119: An error in the HTTP parsing loop when the system appends segmented request bodies without checking write boundaries.
• CVE-2026-34120: A failure in asynchronous parsing for local video streams due to poor boundary validation on streaming inputs.

All three of these vulnerabilities carry a high CVSS v4.0 severity score of 7.1.

CVE-2026-34121: Authentication Bypass

The most severe flaw in this advisory is an authentication bypass vulnerability within the HTTP handling of the camera’s DS configuration service.

The issue stems from inconsistent parsing and authorization logic when the system checks JSON requests during the authentication process.

An unauthenticated attacker can exploit this by attaching an action that does not require login credentials to a request that contains restricted configuration commands.

This tricks the device into skipping standard authorization checks entirely. Once exploited, the attacker can execute restricted commands without logging in, allowing them to modify the device’s state. This critical flaw has a CVSS v4.0 score of 8.7.

CVE-2026-34122: Stack-Based Buffer Overflow

Another high-severity vulnerability exists within the DS configuration service due to poor input validation.

If an attacker supplies an unusually long value for a specific configuration parameter, they can trigger a stack-based buffer overflow.

Much like the heap overflows, successful exploitation of this flaw leads to a DoS condition.

The camera’s services will crash, or the entire device will forcibly reboot, immediately disrupting video surveillance availability. This vulnerability also holds a CVSS v4.0 score of 7.1.

CVE-2026-34124: Path Expansion Overflow

The final vulnerability in the advisory targets the HTTP request path parsing logic. While the device enforces length limits on raw request paths, it fails to account for the extra length added when those paths are expanded during normalization.

An adjacent attacker can send a manipulated HTTP request that expands beyond the allowed memory limits.

This causes another buffer overflow and memory corruption event. The end result is a system interruption or forced reboot, effectively taking the camera offline. This flaw is rated with a high CVSS v4.0 score of 7.1.

These vulnerabilities specifically impact the TP-Link Tapo C520WS v2.6 running firmware versions older than 1.2.4 Build 260326 Rel.24666n.

TP-Link strongly urges all users with affected devices to upgrade their firmware immediately to mitigate these threats.

Users should log into their device’s management interface or use the Tapo mobile application to check for and apply the latest available firmware update.

By keeping your Internet of Things (IoT) devices updated, you prevent unauthorized users from tampering with your network or disrupting your security monitoring. You can also download the latest patches directly from TP-Link’s official support website.

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