Key points
- The vulnerability affects RIOT OS versions prior to 2026.04.
- It requires the MODULE_ATWINC15X0_DYNAMIC_CONNECT feature to be enabled.
- A nearby attacker can trigger the flaw using a malformed SSID.
A nearby adversary can compromise RIOT OS devices by broadcasting a specially crafted Wi-Fi network name. This action triggers a buffer overflow in the ATWINC15x0 driver, potentially granting the attacker full control over the embedded system or causing a denial of service. The issue arises during the standard Wi-Fi scanning process, meaning no prior authentication or user interaction is required to initiate the attack.
In plain English
The problem lies in how the operating system handles network names. When the device scans for available Wi-Fi networks, it copies the name of each network into a memory buffer. The code responsible for this copy operation, specifically the _atwinc15x0_sta_set_current_ssid function, fails to check the length of the incoming name. If an attacker broadcasts a name that is longer than the allocated space, the extra data spills over, corrupting adjacent memory.
The background
RIOT is an open-source operating system designed for microcontrollers and Internet of Things devices. According to the National Vulnerability Database, this specific flaw, identified as CVE-2026-102693, is rated with a CVSS score of 9.6, classifying it as critical. The vulnerability is linked to CWE-120 and CWE-121, which describe buffer errors. It only affects systems where the MODULE_ATWINC15X0_DYNAMIC_CONNECT module is active.
What changes now
The RIOT OS development team has released version 2026.04 to address this security gap. This update patches the ATWINC15x0 driver to properly handle SSID lengths, preventing the memory corruption. Systems running versions older than 2026.04 remain exposed to this risk. Users should verify their current version and apply the update to mitigate the threat of remote code execution or system crashes caused by oversized network identifiers.
The attacker's path
In this scenario, the attacker exploits a weakness in input validation during a routine operational phase. By manipulating the environment rather than the device directly, they bypass traditional access controls. This technique serves as an initial access vector, allowing an intruder to establish a foothold without credentials. Teams usually monitor for unusual Wi-Fi beacon patterns or unexpected system reboots as indicators of such activity, checking whether devices are processing untrusted network advertisements securely.
What to do and how to stay safe: RIOT OS
- Audit your inventory to identify all devices running RIOT OS versions prior to 2026.04.
- Verify if the MODULE_ATWINC15X0_DYNAMIC_CONNECT feature is enabled on affected systems.
- Apply the 2026.04 update once the vendor provides it to patch the driver vulnerability.
- Monitor network logs for anomalous Wi-Fi scanning behaviour or unexpected device crashes.
Step-by-step guide: Emergency Patching: Correcting Five Common Operational Errors
General security guidance from the RedTeam Log newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is the CVSS score for this vulnerability?
The National Vulnerability Database rates CVE-2026-102693 with a CVSS score of 9.6, which is classified as critical.
Which versions of RIOT OS are affected?
All versions of RIOT OS prior to 2026.04 are affected by this buffer overflow vulnerability in the ATWINC15x0 driver.
Is a fix available for this issue?
Yes, the issue is fixed in RIOT OS version 2026.04, which includes the necessary patches for the driver.
