CVE-2026-5079— multer vulnerable to Denial of Service via deeply nested field names

multer vulnerable to Denial of Service via deeply nested field names

Impact: multer versions 1.0.0 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service via deeply nested field names in multipart form data. The append-field dependency parses bracket notation in field names with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this. Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease) and configure the new limits.fieldNestingDepth option to the minimum depth their application requires. Workarounds: Set limits.fields to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

未加控制的资源消耗(资源穷尽)

expressjs Multer 资源管理错误漏洞

expressjs Multer是expressjs组织开源的一个用于Node.js中间件。 expressjs Multer 1.0.0版本至2.2.0之前版本和3.0.0-alpha.1版本至3.0.0-alpha.2之前版本存在资源管理错误漏洞，该漏洞源于嵌套字段名解析无限制，可能导致攻击者通过特制的多部分表单数据强制分配深度嵌套的对象结构，消耗CPU和内存，造成拒绝服务。

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