CVE-2025-47935: 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
Other sources
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 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. Users should upgrade to 2.0.0 to receive a patch. No known workarounds are available.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-47935?
CVE-2025-47935 is classified as a moderate severity vulnerability due to its potential for resource exhaustion and memory leaks.
How do I fix CVE-2025-47935?
To fix CVE-2025-47935, upgrade Multer to version 2.0.0 or later.
What types of systems are affected by CVE-2025-47935?
CVE-2025-47935 affects systems using versions of Node.js Multer prior to 2.0.0.
What kind of issue does CVE-2025-47935 cause?
CVE-2025-47935 causes issues related to resource exhaustion and memory leaks due to improper stream handling.
Is there a workaround for CVE-2025-47935?
There is no official workaround for CVE-2025-47935; upgrading is the recommended action.