{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.3.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4e8edf50dbb5ddec213b6253642cbc08ce0225a7"
            }
          ],
          "repo": "https://github.com/expressjs/multer",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qvfw-j98x-7q72"
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-362"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77063.json"
  },
  "details": "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",
  "modified": "2026-09-05T03:30:42.792436828Z",
  "published": "2026-08-28T19:54:58.473Z",
  "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-2026-77063.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/expressjs/multer/security/advisories/GHSA-qvfw-j98x-7q72"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-77063"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "multer vulnerable to file size limit bypass via async fileFilter race condition"
}