Vulnerability Details 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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 14.4%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-27703
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cpe:2.3:o:riot-os:riot:2013.08
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cpe:2.3:o:riot-os:riot:2014.01
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cpe:2.3:o:riot-os:riot:2014.05
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cpe:2.3:o:riot-os:riot:2014.12
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cpe:2.3:o:riot-os:riot:2015.09
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cpe:2.3:o:riot-os:riot:2015.12
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cpe:2.3:o:riot-os:riot:2016.04
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cpe:2.3:o:riot-os:riot:2016.07
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cpe:2.3:o:riot-os:riot:2016.10
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cpe:2.3:o:riot-os:riot:2017.01
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cpe:2.3:o:riot-os:riot:2017.04
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cpe:2.3:o:riot-os:riot:2017.07
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cpe:2.3:o:riot-os:riot:2017.10
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cpe:2.3:o:riot-os:riot:2018.01
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cpe:2.3:o:riot-os:riot:2018.04
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cpe:2.3:o:riot-os:riot:2018.07
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cpe:2.3:o:riot-os:riot:2018.10
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cpe:2.3:o:riot-os:riot:2018.10.1
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cpe:2.3:o:riot-os:riot:2019.01
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cpe:2.3:o:riot-os:riot:2019.04
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cpe:2.3:o:riot-os:riot:2019.07
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cpe:2.3:o:riot-os:riot:2019.10
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cpe:2.3:o:riot-os:riot:2020.01
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cpe:2.3:o:riot-os:riot:2020.01.1
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cpe:2.3:o:riot-os:riot:2020.04
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cpe:2.3:o:riot-os:riot:2021.01
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cpe:2.3:o:riot-os:riot:2021.04
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cpe:2.3:o:riot-os:riot:2021.07
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cpe:2.3:o:riot-os:riot:2021.10
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cpe:2.3:o:riot-os:riot:2022.01
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cpe:2.3:o:riot-os:riot:2022.04
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cpe:2.3:o:riot-os:riot:2022.07
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cpe:2.3:o:riot-os:riot:2022.10
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cpe:2.3:o:riot-os:riot:2023.01
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cpe:2.3:o:riot-os:riot:2023.04
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cpe:2.3:o:riot-os:riot:2023.07
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cpe:2.3:o:riot-os:riot:2023.10
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cpe:2.3:o:riot-os:riot:2024.01
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cpe:2.3:o:riot-os:riot:2024.04
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cpe:2.3:o:riot-os:riot:2024.07
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cpe:2.3:o:riot-os:riot:2024.10
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cpe:2.3:o:riot-os:riot:2025.01
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cpe:2.3:o:riot-os:riot:2025.04
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cpe:2.3:o:riot-os:riot:2025.07
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cpe:2.3:o:riot-os:riot:2025.10
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cpe:2.3:o:riot-os:riot:2026.01