{"cve":"CVE-2026-82333","nvd":{"published":"2026-08-28T22:16:57.037","modified":"2026-09-02T14:45:57.747","status":"Analyzed","description":"multer is a middleware for handling multipart/form-data in Node.js. A small multipart request with two specially crafted text field names can make multer's field parser synchronously iterate a maximum-length sparse array, blocking the event loop so the process cannot handle other requests. A large numeric array index in the first field allocates a maximum-length sparse array, and a second field with a non-numeric key then triggers a full-length iteration inside the append-field dependency. All versions before 2.3.0 are affected, and this is a remotely triggerable denial of service. multer 2.3.0 adds an opt-in fieldArrayIndexLimit option that rejects oversized array indexes. Upgrade to multer 2.3.0 and set limits.fieldArrayIndexLimit to the largest array index your application needs to remediate.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/expressjs/multer/security/advisories/GHSA-535w-7cp7-47q4"],"products":["expressjs:multer"],"source":"nvd","synced_at":"2026-10-19T22:50:50.842544443+00:00"},"epss":{"cve":"CVE-2026-82333","score":0.00367,"percentile":0.30555,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-535w-7cp7-47q4","url":"https://osv.dev/vulnerability/GHSA-535w-7cp7-47q4","summary":"multer vulnerable to Denial of Service via oversized array index in field names","modified":"2026-09-08T21:45:04.619334872Z","packages":[{"ecosystem":"npm","name":"multer","purl":"pkg:npm/multer","ranges":["<2.3.0"],"fixed":["2.3.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}