CVE-2025-47935: Multer Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-44fp-w29j-9vj5
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CVSS 7.5
CWE-401
Published
Advisory Summary

CVE-2025-47935 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-401: Missing Release of Memory after Effective Lifetime) affecting Multer libraries in the npm ecosystem. The issue involves multer vulnerable to denial of service via memory leaks from unclosed streams. Remediation is available by upgrading affected packages to version 2.0.0.

CVE-2025-47935 at a Glance

CVE Identifier CVE-2025-47935
GHSA Identifier GHSA-44fp-w29j-9vj5
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-401: Missing Release of Memory after Effective Lifetime
Affected Product Multer
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2025-47935

To remediate this vulnerability, upgrade all affected Multer dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

multer fixed: 2.0.0 
npm install multer@2.0.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls multer

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-47935, inspect your project dependencies using npm:

npm ls multer

Analyze the terminal output to locate any version of Multer in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.0), your application is affected.

Note: The npm ls multer command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-401: Missing Release of Memory after Effective Lifetime, where the product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse. In Multer, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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

CVE-2025-47935 Affected Multer Versions

1 component(s)
Fixed Versions:
2.0.0
Product / Package Ecosystem Affected Versions Fixed Version
multer
npm/multer
npm
< 2.0.0
2.0.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/expressjs/multer/security/advisories/GHSA-44fp-w29j-9vj5
NVD — CVE-2025-47935 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-47935
Multer Source Repository REPOSITORY
https://github.com/expressjs/multer/pull/1120
Security Fix Commit FIX COMMIT
https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665
Multer Source Repository REPOSITORY
https://github.com/expressjs/multer

Frequently Asked Questions

What is CVE-2025-47935?
CVE-2025-47935 is a security vulnerability in Multer involving Multer vulnerable to Denial of Service via memory leaks from unclosed streams under CWE-401: Missing Release of Memory after Effective Lifetime.
Which Multer versions are affected?
Affected versions include releases prior to 2.0.0 across affected packages: multer.
What version fixes CVE-2025-47935?
Upgrading to 2.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is multer affected?
Yes, multer is affected in releases prior to 2.0.0. Upgrade your dependency to 2.0.0 or later.
What is the CVSS score of CVE-2025-47935?
CVE-2025-47935 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-47935?
CVE-2025-47935 is classified under CWE-401: Missing Release of Memory after Effective Lifetime (The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.).
How can I check npm dependencies for CVE-2025-47935?
Run the dependency tree command: 'npm ls multer'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-44fp-w29j-9vj5",
  "modified" : "2025-05-19T22:04:17Z",
  "published" : "2025-05-19T22:04:17Z",
  "aliases" : [ "CVE-2025-47935" ],
  "summary" : "Multer vulnerable to Denial of Service via memory leaks from unclosed streams",
  "details" : "### Impact\n\nMulter <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.\n\nThis 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.\n\n\n### Patches\n\nUsers should upgrade to `2.0.0`\n\n\n### Workarounds\n\nNone\n\n### References\n\n- https://github.com/expressjs/multer/pull/1120\n- https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "multer"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/expressjs/multer/security/advisories/GHSA-44fp-w29j-9vj5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-47935"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/expressjs/multer/pull/1120"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/expressjs/multer"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-401" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-05-19T22:04:17Z",
    "nvd_published_at" : "2025-05-19T20:15:25Z"
  }
}