← Vulnerability feed

Vulnerability record · CVE-2026-3520 · published 4 March 2026

CVE-2026-3520: Expressjs multer allocation without limits vulnerability

Expressjs · Multer

Multer 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 Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.

8.7 CVSS 4.0 High EPSS 0.94% · top 40.6% CWE-674 · CWE-674CWE-770 · Allocation without limits
8.7CVSS 4.0 base score
0.94%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
9References
15 Jul 2026Last modified by NVD

Description

Multer 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 Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. Users should upgrade to version 2.1.1 to receive a patch. No known workarounds are available.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

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

References

LinkTags
https://cna.openjsf.org/security-advisories.html Third Party Advisory
https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752 Patch
https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2 Vendor Advisory
https://www.cve.org/CVERecord?id=CVE-2026-3520 Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:6174
https://access.redhat.com/errata/RHSA-2026:6802
https://access.redhat.com/security/cve/CVE-2026-3520
https://bugzilla.redhat.com/show_bug.cgi?id=2444584
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3520.json

Track CVE-2026-3520 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

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

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-2026-5038Expressjs multer vulnerabilityImpact: 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 malfor…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-2026-3520), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.