{"id":"CVE-2026-82333","state":"PUBLISHED","title":"multer vulnerable to Denial of Service via oversized array index in field names","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.","publishedAt":"2026-08-28T20:12:21.355Z","updatedAt":"2026-08-31T18:39:14.067Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"openjs"},"assigner":"openjs","products":["multer multer"],"affected":[{"vendor":"multer","product":"multer","packageURL":"pkg:npm/multer","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.3.0","versionType":"semver"},{"version":"2.3.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/expressjs/multer/security/advisories/GHSA-535w-7cp7-47q4","https://cna.openjsf.org/security-advisories.html"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82333.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82333","state":"PUBLISHED","datePublished":"2026-08-28T20:12:21.355Z","dateUpdated":"2026-08-31T18:39:14.067Z","assignerShortName":"openjs","assignerOrgId":"ce714d77-add3-4f53-aff5-83d477b104bb","dateReserved":"2026-08-28T15:22:56.556Z"},"containers":{"cna":{"title":"multer vulnerable to Denial of Service via oversized array index in field names","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"multer","product":"multer","packageURL":"pkg:npm/multer","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.3.0","versionType":"semver"},{"version":"2.3.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/expressjs/multer/security/advisories/GHSA-535w-7cp7-47q4"},{"url":"https://cna.openjsf.org/security-advisories.html"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]}],"providerMetadata":{"shortName":"openjs","orgId":"ce714d77-add3-4f53-aff5-83d477b104bb","dateUpdated":"2026-08-28T20:12:21.355Z"},"credits":[{"lang":"en","type":"reporter","value":"O4FDev"},{"lang":"en","type":"remediation developer","value":"UlisesGascon"},{"lang":"en","type":"remediation developer","value":"arpitjain099"}],"x_generator":{"engine":"cve-kit 1.0.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T18:39:05.971663Z","id":"CVE-2026-82333","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T18:39:14.067Z"}}]}}}