Home/CVE/Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allo
CVE

CVE-2026-3520

Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allo

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.

HIGH · CVSS 7.5 EPSS 0.00067
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-674Uncontrolled Recursion
▤

Affected Products & Versions

1
expressjs multer< 2.1.1
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
npm multer HIGH fixed in 2.1.1
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · ce714d77-add3-4f53-aff5-83d477b104bb
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD04 Mar 2026 · 05:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

2
rhsaRHSA-2026:6174Important
rhsaRHSA-2026:6802Important
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://cna.openjsf.org/security-advisories.htmlThird Party Advisory
https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752Patch
https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2Vendor Advisory
https://www.cve.org/CVERecord?id=CVE-2026-3520Third Party Advisory
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