CVE-2026-77037

multer vulnerable to Denial of Service via file descriptor leak on aborted uploads

Published Aug 28, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qfvm-cv95-jqjf multer vulnerable to Denial of Service via file descriptor leak on aborted uploads
History
Type Values Removed Values Added
First Time appeared Expressjs
Expressjs multer
CPEs cpe:2.3:a:expressjs:multer:2.2.0:*:*:*:*:node.js:*:*
Vendors & Products Expressjs
Expressjs multer
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Multer
Multer multer
Vendors & Products Multer
Multer multer
Type Values Removed Values Added
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.
Title multer vulnerable to Denial of Service via file descriptor leak on aborted uploads
Weaknesses CWE-400
CWE-459
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
openjs
Published
Updated
Aug 31, 2026, 6:41 PM
Reserved
Aug 20, 2026, 9:01 AM
Status
Analyzed
Published
Aug 28, 2026, 10:16 PM
Modified
Sep 2, 2026, 2:47 PM