CVE-2026-107838

RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. From version 2023.07 through version 2026.07, nanocoap_fileserver callers in sys/net/application_layer/nanocoap/fileserver.c ignore a failure returned by _resp_init() when coap_build_reply() cannot fit a response header into the response buffer. A remote client can send a CoAP request with a sufficiently large extended token when nanocoap_token_ext is enabled, causing response initialization to fail while _get_file() or _get_directory() continues with stale response state. The path then reaches _calc_szx2() and its pdu->payload_len > reserve assertion, terminating the affected service or device task. No fixed release is available as of this review.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/RIOT-OS/RIOT/commit/d3a47289c58d108575a19e623e4d3f647659e743
https://github.com/RIOT-OS/RIOT/pull/22745
https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-39j3-3v73-5mj2

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-2026-107838

Mitre link : CVE-2026-107838

CVE.ORG link : CVE-2026-107838

JSON object : View

Products Affected

No product.

CWE

CWE-252

Unchecked Return Value

CWE-617

Reachable Assertion

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