CVE-2026-77037
Description
A flaw was found in multer, a Node.js middleware for handling multipart/form-data. A remote attacker can exploit a file descriptor leak by sending repeated aborted or malformed multipart uploads. This can exhaust system resources, leading to a denial of service (DoS) for the affected application.
Statement
A file descriptor leak vulnerability was found in multer, a Node.js middleware for handling multipart/form-data. When using multer's built-in diskStorage engine, aborted or truncated uploads cause the disk storage engine to remove the visible file but fail to close the underlying write file descriptor. A remote attacker able to reach an upload route can send repeated aborted or malformed multipart uploads, each one leaking a file descriptor and retaining disk blocks until the process exits, which can exhaust system resources and cause a denial of service. This vulnerability only affects applications using multer's diskStorage; applications using memoryStorage or custom storage engines are not affected.
Mitigation
Upgrade to multer 2.3.0 or later, which properly closes the destination write stream on abnormal source termination and defers cleanup until the stream has closed.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Other); DoS: Resource Consumption (Memory); DoS: Resource Consumption (CPU)
An attacker that can influence the allocation of resources that are not properly released could deplete the available resource pool and prevent all other processes from accessing the same type of resource. Frequently-affected resources include memory, CPU, disk space, power or battery, etc.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
