CVE-2026-27703: RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. In…

PriorityP357critical9.8CVSS 3.1

AVNACLPRNUINSUCHIHAH

EPSS

0.48%

38.0th percentile

RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. In 2026.01 and earlier, the default handler for the well_known_core resource coap_well_known_core_default_handler writes user-provided option data and other data into a fixed size buffer without validating the buffer is large enough to contain the response. This vulnerability allows an attacker to corrupt neighboring stack location, including security-sensitive addresses like the return address, leading to denial of service or arbitrary code execution.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
riot-os	riot	<= 2026.01	—

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