multer vulnerable to Denial of Service via a pending asynchronous fileFilter after request teardown
### Impact When `multer` is configured with an asynchronous `fileFilter`, a single request can crash the Node.js process. If a request is aborted (for example when one file is rejected) while another file's async `fileFilter` is still pending, the pending callback later resumes a parsing stream that multer has already torn down. busboy then emits an error on a stream that no longer has an error listener, which Node raises as an unhandled `'error'` event, and the process exits. A single unauthenticated request is enough, so any application using `multer` with an asynchronous `fileFilter` is affected, regardless of storage engine. Uploads using a synchronous `fileFilter` are not affected. ### Patches Users should upgrade to `multer` `2.5.0` or later. ### Workarounds Use a synchronous `fileFilter`.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-113872US | — | Exploit | ||
multer is a middleware for Node.js that handles multipart/form-data file uploads. In versions from 2.0.0 before 2.5.0, when multer is configured with an asynchronous fileFilter, a… | ||||
references
External citations — patches, advisories, analysis.
- https://cna.openjsf.org/security-advisories.htmlWEB
- https://github.com/expressjs/multerPACKAGE
- https://github.com/expressjs/multer/commit/80a2d9df1dfd63b5fab631b8b9966164ed647adfWEB
- https://github.com/expressjs/multer/releases/tag/v2.5.0WEB
- https://github.com/expressjs/multer/security/advisories/GHSA-q7qp-rjg7-q26mWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-113872ADVISORY
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