CVE-2026-113872 multer vulnerable to Denial of Service via a pending asynchronous fileFilter after request teardown
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-113872?
CVE-2026-113872 is a high-severity vulnerability in multer, published on 22 Oct 2026.
Official description
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 single request can crash the Node.js process. If the request is aborted while one file's asynchronous fileFilter is still pending, the pending callback later resumes a parsing stream that multer has already torn down, and the underlying parser emits an error on a stream that no longer has an error listener, which Node raises as an unhandled error event so the process exits. Any application using multer with an asynchronous fileFilter is affected regardless of storage engine, while uploads using a synchronous fileFilter are not affected. The issue is fixed in multer 2.5.0, and users should upgrade to 2.5.0 or later. As a workaround, use a synchronous fileFilter.
Which versions are affected by CVE-2026-113872?
2 open source packages ship an affected version, including multer.
| Package | Affected | Fixed in |
|---|---|---|
multer npm | From 2.0.0 | 2.5.0 |
multer npm | From 2.0.0 | 2.5.0 |
How do I fix CVE-2026-113872?
Upgrade multer to 2.5.0 or later.
Is CVE-2026-113872 being exploited?
There is no known exploitation of CVE-2026-113872 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as CLSA-2026-1793097623, CLSA-2026-1793098630, ECHO-f4b8-4ad8-46ee, GHSA-q7qp-rjg7-q26m, ROOT-APP-NPM-CVE-2026-113872.