{"id":"CVE-2026-66729","summary":"facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart MIME Body Parser","details":"facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an empty field name. Attackers can trigger a uint32_t wraparound in http_mime_parser.h causing an out-of-bounds memory read past the name pointer, resulting in a bus fault that crashes the handling worker with a single POST request.","modified":"2026-07-29T03:31:56.106510870Z","published":"2026-07-27T16:52:34.776Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-125"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66729.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66729.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66729"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/facil-io-integer-underflow-dos-via-multipart-mime-body-parser"},{"type":"PACKAGE","url":"https://github.com/boazsegev/facil.io"},{"type":"EVIDENCE","url":"https://github.com/theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-Server-Crash"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/boazsegev/facil.io","events":[{"introduced":"13472f2f025498828b0823705c863602bdb08b70"},{"last_affected":"512a354dbd31e1895647df852d1565f9d408ed91"}],"database_specific":{"extracted_events":[{"introduced":"0.6.0"},{"last_affected":"0.7.6"}],"source":"AFFECTED_FIELD"}}],"versions":["0.7.6","0.7.3","0.7.2","0.7.0","0.7.0.beta8","0.7.0.beta7","0.7.0.beta6","0.7.0.beta5","0.7.0.beta4","0.7.0.beta3","0.7.0.beta2","0.7.0.beta1","0.6.4","0.6.3","0.6.2","0.6.1","0.6.0","0.6.0.beta.8","0.6.0.beta.7","0.6.0.beta.6","0.6.0.beta.5","0.6.0.beta.4","0.6.0.beta.3","0.6.0.beta.2","0.6.0.beta","0.6.0.dev"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66729.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}