CVE-2026-3520
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 0.8% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.8% in the next 30 days (EPSS).
- Severity: 8.7 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.8% · EPSS, next 30 days
- Weakness
- CWE-674
- Record status
- Modified
Affected
- Expressjs Multer < 2.1.1
Attack profile CVSS 4.0 · 8.7
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
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:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-3520.md and follow it. Check whether this project is affected by CVE-2026-3520. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752
- https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2
References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752
- https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2
- https://www.cve.org/CVERecord?id=CVE-2026-3520
- 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