Vulnerability · 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.
Published Mar 11, 2026 · corrected/updated Jun 17, 2026 · riot-os riot · evidence confidence high
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.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-27703 is a critical public vulnerability record for riot-os riot. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether riot-os riot is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: riot-os/riot. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 9.8 (technical impact); EPSS 0.6% (30-day exploitation probability). It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-787. Sources contributing to this record: cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Mar 11, 2026 · NIST NVD
Detected
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
Jun 17, 2026 · NIST NVD
Updated
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
Affected
Enter an installed version to get a verified affected / not-affected result against the ranges below.
- cpe riot-os/riotversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-27703
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-27703
30-day exploitation probability 0.6%
first.org - NIST NVDVulnerability recordCVE-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 use
nvd.nist.gov