{"id":"CVE-2026-3520","aliases":["EUVD-2026-9423","GHSA-5528-5vmv-3xc2","ROOT-APP-NPM-CVE-2026-3520"],"status":"published","title":"Multer vulnerable to Denial of Service via uncontrolled recursion","description":"Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.","severity":{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00818,"percentile":0.57421,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-674","CWE-770"],"published":"2026-03-04T16:17:18Z","modified":"2026-10-29T19:15:03Z","fixes":[{"ecosystem":"npm","package":"multer","fixed_in":["2.1.1"],"sources":["ghsa","osv"]},{"ecosystem":"Root:npm","package":"multer","fixed_in":["1.4.4-lts.1-aikido.3","1.4.5-lts.2-aikido.9","1.4.4-lts.1-aikido.4","1.4.4-aikido.2","1.4.2-aikido.1","2.0.2-aikido.4","1.4.5-lts.1-aikido.2","1.4.5-lts.1-aikido.3","2.0.2-aikido.5","2.0.2-aikido.6","1.4.4-aikido.3","1.4.4-lts.1-aikido.1","1.4.4-aikido.4","1.4.5-lts.1-aikido.1","1.4.4-lts.1-aikido.2","1.4.4-aikido.5","1.4.4-aikido.6","1.4.2-aikido.2","1.4.5-lts.2-aikido.7","1.4.5-lts.2-aikido.8","2.1.1-aikido.4","2.0.2-aikido.7","2.1.1-aikido.3","2.1.1-aikido.1","2.1.1-aikido.2"],"sources":["osv"]},{"ecosystem":"Root:npm","package":"@rootio/multer","fixed_in":["1.4.4-lts.1-root.io.3","1.4.5-lts.2-root.io.9","2.0.2-root.io.1","2.0.2-root.io.2","2.0.2-root.io.3","1.4.4-lts.1-root.io.4","1.4.4-root.io.2","1.4.4-root.io.1","1.4.2-root.io.1","2.0.2-root.io.4","1.4.5-lts.1-root.io.2","1.4.5-lts.1-root.io.3","2.0.2-root.io.5","2.0.2-root.io.6","1.4.4-root.io.3","1.4.4-lts.1-root.io.1","1.4.4-root.io.4","1.4.5-lts.1-root.io.1","1.4.4-lts.1-root.io.2","1.4.4-root.io.5","1.4.4-root.io.6","1.4.2-root.io.2","1.4.5-lts.2-root.io.7","1.4.5-lts.2-root.io.8","2.1.1-root.io.4","2.0.2-root.io.7","2.1.1-root.io.3","2.1.1-root.io.1","2.1.1-root.io.2"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"multer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1"}]}]},{"source":"osv","ecosystem":"npm","package":"multer","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.1.1"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"multer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.4-lts.1-aikido.3"},{"fixed":"1.4.5-lts.2-aikido.9"},{"fixed":"1.4.4-lts.1-aikido.4"},{"fixed":"1.4.4-aikido.2"},{"fixed":"1.4.2-aikido.1"},{"fixed":"2.0.2-aikido.4"},{"fixed":"1.4.5-lts.1-aikido.2"},{"fixed":"1.4.5-lts.1-aikido.3"},{"fixed":"2.0.2-aikido.5"},{"fixed":"2.0.2-aikido.6"},{"fixed":"1.4.4-aikido.3"},{"fixed":"1.4.4-lts.1-aikido.1"},{"fixed":"1.4.4-aikido.4"},{"fixed":"1.4.5-lts.1-aikido.1"},{"fixed":"1.4.4-lts.1-aikido.2"},{"fixed":"1.4.4-aikido.5"},{"fixed":"1.4.4-aikido.6"},{"fixed":"1.4.2-aikido.2"},{"fixed":"1.4.5-lts.2-aikido.7"},{"fixed":"1.4.5-lts.2-aikido.8"},{"fixed":"2.1.1-aikido.4"},{"fixed":"2.0.2-aikido.7"},{"fixed":"2.1.1-aikido.3"},{"fixed":"2.1.1-aikido.1"},{"fixed":"2.1.1-aikido.2"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"@rootio/multer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.4-lts.1-root.io.3"},{"fixed":"1.4.5-lts.2-root.io.9"},{"fixed":"2.0.2-root.io.1"},{"fixed":"2.0.2-root.io.2"},{"fixed":"2.0.2-root.io.3"},{"fixed":"1.4.4-lts.1-root.io.4"},{"fixed":"1.4.4-root.io.2"},{"fixed":"1.4.4-root.io.1"},{"fixed":"1.4.2-root.io.1"},{"fixed":"2.0.2-root.io.4"},{"fixed":"1.4.5-lts.1-root.io.2"},{"fixed":"1.4.5-lts.1-root.io.3"},{"fixed":"2.0.2-root.io.5"},{"fixed":"2.0.2-root.io.6"},{"fixed":"1.4.4-root.io.3"},{"fixed":"1.4.4-lts.1-root.io.1"},{"fixed":"1.4.4-root.io.4"},{"fixed":"1.4.5-lts.1-root.io.1"},{"fixed":"1.4.4-lts.1-root.io.2"},{"fixed":"1.4.4-root.io.5"},{"fixed":"1.4.4-root.io.6"},{"fixed":"1.4.2-root.io.2"},{"fixed":"1.4.5-lts.2-root.io.7"},{"fixed":"1.4.5-lts.2-root.io.8"},{"fixed":"2.1.1-root.io.4"},{"fixed":"2.0.2-root.io.7"},{"fixed":"2.1.1-root.io.3"},{"fixed":"2.1.1-root.io.1"},{"fixed":"2.1.1-root.io.2"}]}]}],"products":[{"vendor":"expressjs","product":"multer"},{"vendor":"red hat","product":"red hat developer hub 1.8"},{"vendor":"red hat","product":"red hat developer hub 1.9"},{"vendor":"red hat","product":"self-service automation portal 2"}],"references":[{"url":"https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2","tags":["Vendor Advisory","advisory","web"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-3520","tags":["Third Party Advisory","web"]},{"url":"https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752","tags":["Patch","fix","web"]},{"url":"https://cna.openjsf.org/security-advisories.html","tags":["Third Party Advisory","advisory","web"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-3520","tags":["vdb-entry","x_refsource_REDHAT","advisory"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2444584","tags":["issue-tracking","x_refsource_REDHAT","report"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3520.json","tags":["x_sadp-csaf-vex","web"]},{"url":"https://access.redhat.com/errata/RHSA-2026:6174","tags":["vendor-advisory","x_refsource_REDHAT","advisory"]},{"url":"https://access.redhat.com/errata/RHSA-2026:6802","tags":["vendor-advisory","x_refsource_REDHAT","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3520","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-5528-5vmv-3xc2"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3520.json","tags":["advisory"]},{"url":"https://github.com/expressjs/multer","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-3520","title":"Multer vulnerable to Denial of Service via uncontrolled recursion","description":"Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.","status":"published","published":"2026-03-04T16:17:18.962Z","modified":"2026-07-15T01:03:04.43Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"adp"}],"cwes":["CWE-674","CWE-770"],"updated_at":"2026-11-02T13:49:09.229322Z"}],"euvd":[{"id":"EUVD-2026-9423","description":"Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.","status":"published","published":"2026-03-04T16:17:18Z","modified":"2026-07-15T01:03:04Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:19:56.47701Z"}],"ghsa":[{"id":"GHSA-5528-5vmv-3xc2","title":"Multer Vulnerable to Denial of Service via Uncontrolled Recursion","description":"### Impact\n\nA vulnerability in Multer versions \u003c 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow.\n\n### Patches\n\nUsers should upgrade to `2.1.1`\n\n### Workarounds\n\nNone\n\n### Resources\n\n- https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2\n- https://www.cve.org/CVERecord?id=CVE-2026-3520\n- https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752\n- https://cna.openjsf.org/security-advisories.html","status":"published","published":"2026-03-05T00:27:50Z","modified":"2026-03-05T00:27:52Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-674"],"updated_at":"2026-11-02T14:39:31.060223Z"}],"nvd":[{"id":"CVE-2026-3520","description":"Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.","status":"published","published":"2026-03-04T17:16:22.61Z","modified":"2026-07-15T02:21:00.833Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-674","CWE-770"],"updated_at":"2026-11-02T14:12:07.420927Z"}],"osv":[{"id":"CVE-2026-3520","title":"Multer vulnerable to Denial of Service via uncontrolled recursion","description":"Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.","status":"published","published":"2026-03-04T16:17:18.962Z","modified":"2026-10-28T02:30:21.042337216Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-674"],"updated_at":"2026-11-02T15:45:02.673625Z"},{"id":"GHSA-5528-5vmv-3xc2","title":"Multer Vulnerable to Denial of Service via Uncontrolled Recursion","description":"### Impact\n\nA vulnerability in Multer versions \u003c 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow.\n\n### Patches\n\nUsers should upgrade to `2.1.1`\n\n### Workarounds\n\nNone\n\n### Resources\n\n- https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2\n- https://www.cve.org/CVERecord?id=CVE-2026-3520\n- https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752\n- https://cna.openjsf.org/security-advisories.html","status":"published","published":"2026-03-05T00:27:50Z","modified":"2026-09-10T03:50:59.77026201Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-674"],"updated_at":"2026-11-02T15:46:37.864461Z"},{"id":"ROOT-APP-NPM-CVE-2026-3520","title":"CVE-2026-3520 in multer - Patched by Root","description":"Root has patched CVE-2026-3520 in the multer package for Root:npm. Multiple fixed versions available.","status":"published","published":"2026-10-29T18:47:25Z","modified":"2026-10-29T19:15:03.210340998Z","updated_at":"2026-11-02T15:53:27.649662Z"}]}}