{"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": "2026-10-09T17:55:34.670Z"}, "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"}}}}

{}

{"affected": [{"affectedData": [{"product": "RIOT", "vendor": "RIOT-OS", "versions": [{"status": "affected", "version": ">= 2023.07, <= 2026.07"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-107838", "lastModified": "2026-10-09T18:17:05.640", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-10-09T18:17:05.640", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/RIOT-OS/RIOT/commit/d3a47289c58d108575a19e623e4d3f647659e743"}, {"source": "security-advisories@github.com", "url": "https://github.com/RIOT-OS/RIOT/pull/22745"}, {"source": "security-advisories@github.com", "url": "https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-39j3-3v73-5mj2"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-252"}, {"lang": "en", "value": "CWE-617"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[2023.07,2026.07]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "RIOT", "source": "cna", "vendor": "RIOT-OS"}, "product": "riot", "vendor": "riot-os"}], "created": "2026-10-09T19:30:11.102221+00:00", "updated": "2026-10-09T20:00:16.766823+00:00", "vendors": ["riot-os", "riot-os$PRODUCT$riot"]}