{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-107838", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-10-08T22:34:49.290Z", "datePublished": "2026-10-09T17:55:34.670Z", "dateUpdated": "2026-10-13T17:07:38.700Z"}, "containers": {"cna": {"title": "RIOT: nanocoap_fileserver ignores response initialization failure, leading to reachable assertion", "problemTypes": [{"descriptions": [{"cweId": "CWE-252", "lang": "en", "description": "CWE-252: Unchecked Return Value", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-617", "lang": "en", "description": "CWE-617: Reachable Assertion", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-39j3-3v73-5mj2", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-39j3-3v73-5mj2"}, {"name": "https://github.com/RIOT-OS/RIOT/pull/22745", "tags": ["x_refsource_MISC"], "url": "https://github.com/RIOT-OS/RIOT/pull/22745"}, {"name": "https://github.com/RIOT-OS/RIOT/commit/d3a47289c58d108575a19e623e4d3f647659e743", "tags": ["x_refsource_MISC"], "url": "https://github.com/RIOT-OS/RIOT/commit/d3a47289c58d108575a19e623e4d3f647659e743"}], "affected": [{"vendor": "RIOT-OS", "product": "RIOT", "versions": [{"version": ">= 2023.07, <= 2026.07", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-09T17:55:34.670Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-39j3-3v73-5mj2", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-10-13T17:07:15.908632Z", "id": "CVE-2026-107838", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-13T17:07:38.700Z"}}]}}

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