RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. Prior to 2026.07, nanocoap accepts oversized CoAP Block2 option values without enforcing the 20-bit maximum block number, allowing block offset multiplication to overflow on 32-bit targets. The affected master baseline is commit aeeae69e; the verified fix is later on master and remains unreleased. The oversized value passes from coap_get_blockopt() to coap_block_slicer_init(). A remote CoAP client can send a malformed Block2 option that produces an invalid slice range and can cause out-of-bounds memory access, denial of service, or memory corruption. This vulnerability is fixed in 2026.07.
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Fixes

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History

Fri, 16 Oct 2026 17:00:00 +0000

Type Values Removed Values Added
Description RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. Prior to 2026.07, nanocoap accepts oversized CoAP Block2 option values without enforcing the 20-bit maximum block number, allowing block offset multiplication to overflow on 32-bit targets. The affected master baseline is commit aeeae69e; the verified fix is later on master and remains unreleased. The oversized value passes from coap_get_blockopt() to coap_block_slicer_init(). A remote CoAP client can send a malformed Block2 option that produces an invalid slice range and can cause out-of-bounds memory access, denial of service, or memory corruption. This vulnerability is fixed in 2026.07.
Title RIOT: Potential integer overflow in nanocoap Block2 handling leading to out-of-bounds memory access
Weaknesses CWE-190
CWE-787
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-16T16:48:35.776Z

Reserved: 2026-09-29T16:10:04.076Z

Link: CVE-2026-102692

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-16T17:17:16.980

Modified: 2026-10-16T17:17:16.980

Link: CVE-2026-102692

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses