{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-77063", "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "state": "PUBLISHED", "assignerShortName": "openjs", "dateReserved": "2026-08-20T09:59:20.298Z", "datePublished": "2026-08-28T19:54:58.473Z", "dateUpdated": "2026-08-28T19:54:58.473Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "shortName": "openjs", "dateUpdated": "2026-08-28T19:54:58.473Z"}, "descriptions": [{"lang": "en", "value": "multer is a middleware for handling multipart/form-data in Node.js. When an application uses an asynchronous fileFilter together with the fileSize limit, a race condition in multer's file stream handling can allow a file that exceeds the configured size limit to bypass the size-limit rejection. All versions before 2.3.0 are affected. The impact is limited because the underlying multipart parser still truncates the stream at the size limit, so this is a bypass of the limit rejection rather than uncontrolled resource consumption. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "multer is a middleware for handling multipart/form-data in Node.js. When an application uses an asynchronous fileFilter together with the fileSize limit, a race condition in multer's file stream handling can allow a file that exceeds the configured size limit to bypass the size-limit rejection. All versions before 2.3.0 are affected. The impact is limited because the underlying multipart parser still truncates the stream at the size limit, so this is a bypass of the limit rejection rather than uncontrolled resource consumption. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate."}]}], "affected": [{"vendor": "multer", "product": "multer", "defaultStatus": "unaffected", "versions": [{"versionType": "semver", "status": "affected", "version": "0", "lessThan": "2.3.0"}, {"versionType": "semver", "status": "unaffected", "version": "2.3.0"}], "packageURL": "pkg:npm/multer"}], "references": [{"url": "https://github.com/expressjs/multer/security/advisories/GHSA-qvfw-j98x-7q72"}, {"url": "https://cna.openjsf.org/security-advisories.html"}], "credits": [{"lang": "en", "type": "reporter", "value": "ThinkerHao"}, {"lang": "en", "type": "remediation developer", "value": "bjohansebas"}, {"lang": "en", "type": "remediation reviewer", "value": "UlisesGascon"}], "title": "multer vulnerable to file size limit bypass via async fileFilter race condition", "metrics": [{"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 3.7, "baseSeverity": "LOW"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-362", "lang": "en", "description": "CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')", "type": "CWE"}]}], "x_generator": {"engine": "cve-kit 1.0.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:npm/multer", "product": "multer", "vendor": "multer", "versions": [{"lessThan": "2.3.0", "status": "affected", "version": "0", "versionType": "semver"}, {"status": "unaffected", "version": "2.3.0", "versionType": "semver"}]}], "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "multer is a middleware for handling multipart/form-data in Node.js. When an application uses an asynchronous fileFilter together with the fileSize limit, a race condition in multer's file stream handling can allow a file that exceeds the configured size limit to bypass the size-limit rejection. All versions before 2.3.0 are affected. The impact is limited because the underlying multipart parser still truncates the stream at the size limit, so this is a bypass of the limit rejection rather than uncontrolled resource consumption. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate."}], "id": "CVE-2026-77063", "lastModified": "2026-08-28T22:16:53.760", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 3.7, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 1.4, "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "type": "Secondary"}]}, "published": "2026-08-28T22:16:53.760", "references": [{"source": "ce714d77-add3-4f53-aff5-83d477b104bb", "url": "https://cna.openjsf.org/security-advisories.html"}, {"source": "ce714d77-add3-4f53-aff5-83d477b104bb", "url": "https://github.com/expressjs/multer/security/advisories/GHSA-qvfw-j98x-7q72"}], "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-362"}], "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "type": "Secondary"}]}

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