CVE-2025-7338 Multer vulnerable to Denial of Service via unhandled exception from malformed request
An attacker can crash the application process by sending a malformed multipart upload request to the Multer library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-7338?
CVE-2025-7338 is a high-severity denial of service vulnerability in expressjs multer, published on 17 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability that is present starting in version 1.4.4-lts.1 and prior to version 2.0.2 allows an attacker to trigger a Denial of Service (DoS) by sending a malformed multi-part upload request. This request causes an unhandled exception, leading to a crash of the process. Users should upgrade to version 2.0.2 to receive a patch. No known workarounds are available.
Weakness: CWE-248
Which versions are affected by CVE-2025-7338?
2 open source packages ship an affected version, including multer.
| Package | Affected | Fixed in |
|---|---|---|
multer npm | From 1.4.4-lts.1 | 2.0.2 |
multer npm | From 1.4.4-lts.1 | 2.0.2 |
How do I fix CVE-2025-7338?
Upgrade multer to 2.0.2 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-7338 being exploited?
There is no known exploitation of CVE-2025-7338 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as CLSA-2026-1773879511, ECHO-26b0-db10-57a6, GHSA-fjgf-rc76-4x9p, MINI-72x9-592j-8927, ROOT-APP-NPM-CVE-2025-7338.