CVE-2026-3520: CWE-674: Uncontrolled Recursion in 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.
AI Analysis
Technical Summary
CVE-2026-3520 is a high-severity vulnerability in the expressjs multer middleware before version 2.1.1. It involves uncontrolled recursion triggered by malformed multipart/form-data requests, which can cause a stack overflow and result in a Denial of Service (DoS). The vulnerability is identified as CWE-674 (Uncontrolled Recursion) and CWE-770. The vendor has released version 2.1.1 to patch this issue. Red Hat advisories confirm the vulnerability and recommend upgrading. No known exploits are reported in the wild.
Potential Impact
An attacker can exploit this vulnerability by sending specially crafted malformed requests to applications using vulnerable versions of multer, causing uncontrolled recursion that leads to stack overflow and Denial of Service. This disrupts service availability but does not indicate privilege escalation or data compromise based on the provided data.
Mitigation Recommendations
Users should upgrade multer to version 2.1.1 or later to remediate this vulnerability. No known workarounds are available. Since this is not a cloud service, remediation depends on user action to update the software. Check the vendor advisories at Red Hat for any additional guidance.
CVE-2026-3520: CWE-674: Uncontrolled Recursion in expressjs multer
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 v4.0
Score 8.7high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-3520 is a high-severity vulnerability in the expressjs multer middleware before version 2.1.1. It involves uncontrolled recursion triggered by malformed multipart/form-data requests, which can cause a stack overflow and result in a Denial of Service (DoS). The vulnerability is identified as CWE-674 (Uncontrolled Recursion) and CWE-770. The vendor has released version 2.1.1 to patch this issue. Red Hat advisories confirm the vulnerability and recommend upgrading. No known exploits are reported in the wild.
Potential Impact
An attacker can exploit this vulnerability by sending specially crafted malformed requests to applications using vulnerable versions of multer, causing uncontrolled recursion that leads to stack overflow and Denial of Service. This disrupts service availability but does not indicate privilege escalation or data compromise based on the provided data.
Mitigation Recommendations
Users should upgrade multer to version 2.1.1 or later to remediate this vulnerability. No known workarounds are available. Since this is not a cloud service, remediation depends on user action to update the software. Check the vendor advisories at Red Hat for any additional guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- openjs
- Date Reserved
- 2026-03-04T15:27:42.237Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-3520","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6174","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6802","vendor":"Red Hat"}]
Threat ID: 69a85ed2d1a09e29cb4aee03
Added to database: 03/04/2026, 16:33:22 UTC
Last enriched: 07/15/2026, 09:08:17 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 254
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