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CVE-2026-77037— multer vulnerable to Denial of Service via file descriptor leak on aborted uploads

Quick assessment

Affected
multer multer
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Multer 是 Node.js 中用于处理 multipart/form-data 的中间件。在 2.2.0 版本中，当基于磁盘的上传在写入流结束前被中止或截断时，multer 的磁盘存储引擎会删除可见的文件，但不会关闭底层的写入文件描述符，从而导致出现一个已被删除但仍处于打开状态的描述符。能够访问使用内置磁盘存储的上传路由的远程攻击者可以发送反复被中止或格式错误的 multipart 上传，每次上传都会泄露一个文件描述符，并保留磁盘块，直到进程退出为止，这可能耗尽系统资源并导致服务拒绝（DoS）。该问题已在 m

CVSS 7.5 · High

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-77037

Vulnerability Information
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Vulnerability Title
multer vulnerable to Denial of Service via file descriptor leak on aborted uploads
Source: CVE Program / CVE List V5
Vulnerability Description
multer is a middleware for handling multipart/form-data in Node.js. In version 2.2.0, when a disk-backed upload is aborted or truncated before the write stream finishes, multer's disk storage engine removes the visible file but does not close the underlying write file descriptor, leaving a deleted but still open descriptor. A remote attacker able to reach an upload route using the built-in disk storage 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 resources and cause a denial of service. The issue is fixed in multer 2.3.0, which closes the destination write stream on abnormal source termination and defers cleanup until the stream has closed. Upgrade to multer 2.3.0 to remediate.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
multer multer 2.2.0 ~ 2.3.0 -

II. Public POCs for CVE-2026-77037

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III. Intelligence Information for CVE-2026-77037

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Vendor Advisories for CVE-2026-77037 (1)

Same Patch Batch · multer · 2026-08-28 · 4 CVEs total

CVE-2026-77078 7.5 HIGH multer vulnerable to Denial of Service via crafted multipart field names
CVE-2026-82333 7.5 HIGH multer vulnerable to Denial of Service via oversized array index in field names
CVE-2026-77063 3.7 LOW multer vulnerable to file size limit bypass via async fileFilter race condition

IV. Related Vulnerabilities

Same product: multer
Same vendor: multer
Same weakness: CWE-400

V. Comments for CVE-2026-77037

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