{"id":"CVE-2026-5079","state":"PUBLISHED","title":"multer vulnerable to Denial of Service via deeply nested field names","description":"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.","publishedAt":"2026-06-15T13:56:45.520Z","updatedAt":"2026-06-15T16:00:43.955Z","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":"1.0.0","status":"affected","lessThan":"2.2.0","versionType":"semver"},{"version":"2.2.0","status":"unaffected","versionType":"semver"},{"version":"3.0.0-alpha.1","status":"affected","lessThan":"3.0.0-alpha.2","versionType":"semver"},{"version":"3.0.0-alpha.2","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j","https://cna.openjsf.org/security-advisories.html"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/5xxx/CVE-2026-5079.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-5079","state":"PUBLISHED","datePublished":"2026-06-15T13:56:45.520Z","dateUpdated":"2026-06-15T16:00:43.955Z","assignerShortName":"openjs","assignerOrgId":"ce714d77-add3-4f53-aff5-83d477b104bb","dateReserved":"2026-03-28T19:04:56.443Z"},"containers":{"cna":{"title":"multer vulnerable to Denial of Service via deeply nested field names","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"multer","product":"multer","packageURL":"pkg:npm/multer","defaultStatus":"unaffected","versions":[{"version":"1.0.0","status":"affected","lessThan":"2.2.0","versionType":"semver"},{"version":"2.2.0","status":"unaffected","versionType":"semver"},{"version":"3.0.0-alpha.1","status":"affected","lessThan":"3.0.0-alpha.2","versionType":"semver"},{"version":"3.0.0-alpha.2","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j"},{"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":"2026-06-15T13:56:45.520Z"},"credits":[{"lang":"en","type":"reporter","value":"tndud042713"},{"lang":"en","type":"remediation developer","value":"UlisesGascon"}],"x_generator":{"engine":"cve-kit 1.0.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-15T16:00:29.855724Z","id":"CVE-2026-5079","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":"2026-06-15T16:00:43.955Z"}}]}}}