CVE-2026-107836

RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. In 2026.07 and earlier, the nanoCoAP client function nanocoap_sock_get_slice() in sys/net/application_layer/nanocoap/sock.c accepts a Block2 response when _block_cb() sees the expected block number without also verifying that the server-controlled szx and derived offset match the requested block geometry. A malicious CoAP server can return the expected block number with a larger block size, causing the derived offset to exceed the client slice offset and making ctx->offset - offset underflow in _2buf_slice(). The resulting buffer-relative calculation can read before the payload buffer and crash the client, causing denial of service and potentially exposing adjacent memory. No fixed release is available as of this review.

CVSS

No CVSS.

References

Link	Resource
https://github.com/RIOT-OS/RIOT/commit/49b894cbe091510093273b98d92c4a17167d6839
https://github.com/RIOT-OS/RIOT/pull/22518
https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-x924-p5fq-26pc

Configurations

No configuration.

History

09 Oct 2026, 18:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-09 18:17

Updated : 2026-10-16 17:17

NVD link : CVE-2026-107836

Mitre link : CVE-2026-107836

CVE.ORG link : CVE-2026-107836

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

CWE-191

Integer Underflow (Wrap or Wraparound)

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