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Vulnerability record · CVE-2026-5038 · published 15 June 2026

CVE-2026-5038: Expressjs multer vulnerability

Expressjs · Multer

Impact: multer versions 2.0.0-alpha.1 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service when using diskStorage. Aborted or malformed multipart uploads leave orphaned partial files on disk because the Readable.pipe() call does not propagate the stream destroy signal to the underlying fs.WriteStream. An attacker can exhaust disk space by triggering many aborted uploads, with no application bug required. Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease). Both versions track in-flight write streams and clean them up on the abort path. Workarounds: None.

7.5 CVSS 3.1 High EPSS 0.49% · top 60.5% CWE-459 · CWE-459
7.5CVSS 3.1 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

Impact: multer versions 2.0.0-alpha.1 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service when using diskStorage. Aborted or malformed multipart uploads leave orphaned partial files on disk because the Readable.pipe() call does not propagate the stream destroy signal to the underlying fs.WriteStream. An attacker can exhaust disk space by triggering many aborted uploads, with no application bug required. Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease). Both versions track in-flight write streams and clean them up on the abort path. Workarounds: None.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.7CVE-2026-3520Expressjs multer allocation without limits vulnerabilityMulter is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.1 allows an attacker to trigger a D…EPSS 0.94%8.7CVE-2026-3304Expressjs multer vulnerabilityMulter is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.0 allows an attacker to trigger a D…EPSS 0.86%8.7CVE-2026-2359Expressjs multer vulnerabilityMulter is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.0 allows an attacker to trigger a D…EPSS 0.68%7.5CVE-2026-82333Expressjs multer uncontrolled resource consumption vulnerabilitymulter is a middleware for handling multipart/form-data in Node.js. A small multipart request with two specially crafted text field names can make mu…EPSS 0.49%7.5CVE-2026-77037Expressjs multer uncontrolled resource consumption vulnerabilitymulter 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 wr…EPSS 0.58%7.5CVE-2026-77078Expressjs multer vulnerabilitymulter is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can c…EPSS 0.49%7.5CVE-2026-5079Expressjs multer uncontrolled resource consumption vulnerabilityImpact: 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 d…EPSS 0.49%3.7CVE-2026-77063Expressjs multer race condition vulnerabilitymulter is a middleware for handling multipart/form-data in Node.js. When an application uses an asynchronous fileFilter together with the fileSize li…EPSS 0.23%

Source: NIST National Vulnerability Database (record CVE-2026-5038), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.