RIOT: nanocoap_fileserver ignores response initialization failure, leading to reachable assertion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-107838
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-09 18:17:05 UTC
Updated2026-10-09 18:17:05 UTC
DescriptionRIOT 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-252 | CWE-617 | CWE-252 CWE-252: Unchecked Return Value | CWE-617 CWE-617: Reachable Assertion

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA RIOT-OS RIOT affected >= 2023.07, <= 2026.07 Not specified

References

ReferenceSourceLinkTags
github.com/RIOT-OS/RIOT/commit/d3a47289c58d108575a19e623e4d3f647659e743 [email protected] github.com
github.com/RIOT-OS/RIOT/security/advisories/GHSA-39j3-3v73-5mj2 [email protected] github.com
github.com/RIOT-OS/RIOT/pull/22745 [email protected] github.com
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