CVE-2026-107838

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{"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": "2026-10-16T17:17:04.113", "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"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-107838", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-13T17:07:15.908632Z", "version": "2.0.3"}}]}, "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": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-252"}, {"lang": "en", "value": "CWE-617"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"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"]}