{"id":"CVE-2026-77078","aliases":["GHSA-wc9g-mqfw-jrwm"],"url":"https://o3.security/vulnerability/CVE-2026-77078","summary":"multer vulnerable to Denial of Service via crafted multipart field names","details":"multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.","published":"2026-08-28T20:03:23.114Z","modified":"2026-09-05T03:48:04.995491830Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"multer","fixedVersion":"2.3.0"}],"fix":{"url":"https://github.com/expressjs/multer/commit/87a584e8c8d4da873292635fa1d8c4d78d985b76","label":"expressjs/multer@87a584e"},"references":[{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77078.json"},{"type":"ADVISORY","url":"https://github.com/expressjs/multer/security/advisories/GHSA-wc9g-mqfw-jrwm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77078"},{"type":"WEB","url":"https://github.com/expressjs/multer/commit/87a584e8c8d4da873292635fa1d8c4d78d985b76"},{"type":"PACKAGE","url":"https://github.com/expressjs/multer"},{"type":"WEB","url":"https://github.com/expressjs/multer/releases/tag/v2.3.0"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-05T03:48:04.995491830Z"}}