{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "1.0.0"
              },
              {
                "fixed": "2.2.0"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "869e2138af1d2b9cf62b8abb95e5785aef007b4b"
            },
            {
              "fixed": "2e2af08157c66cbbc76539ccbd8869097a0c8feb"
            }
          ],
          "repo": "https://github.com/expressjs/multer",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-72gw-mp4g-v24j"
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5079.json"
  },
  "details": "Impact: multer versions 1.0.0 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service via deeply nested field names in multipart form data. The append-field dependency parses bracket notation in field names with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this.\n\nPatches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease) and configure the new limits.fieldNestingDepth option to the minimum depth their application requires.\n\nWorkarounds: Set limits.fields to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.",
  "id": "CVE-2026-5079",
  "modified": "2026-07-16T03:30:55.166504294Z",
  "published": "2026-06-15T13:56:45.520Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5079.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5079"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "multer vulnerable to Denial of Service via deeply nested field names"
}