Multer vulnerable to Denial of Service via memory leaks from unclosed streams
### Impact Multer <2.0.0 is vulnerable to a resource exhaustion and memory leak issue due to improper stream handling. When the HTTP request stream emits an error, the internal `busboy` stream is not closed, violating Node.js stream safety guidance. This leads to unclosed streams accumulating over time, consuming memory and file descriptors. Under sustained or repeated failure conditions, this can result in denial of service, requiring manual server restarts to recover. All users of Multer handling file uploads are potentially impacted. ### Patches Users should upgrade to `2.0.0` ### Workarounds None ### References - https://github.com/expressjs/multer/pull/1120 - https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-47935US | — | — | ||
Multer is a node.js middleware for handling `multipart/form-data`. Versions prior to 2.0.0 are vulnerable to a resource exhaustion and memory leak issue due to improper stream hand… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/expressjs/multerPACKAGE
- https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665WEB
- https://github.com/expressjs/multer/pull/1120WEB
- https://github.com/expressjs/multer/security/advisories/GHSA-44fp-w29j-9vj5WEB
- https://nvd.nist.gov/vuln/detail/CVE-2025-47935ADVISORY
Advisories like this name the exposed products attackers go after on your perimeter. See what is exposed on your perimeter with a free passive scan.
Free scan