High 8.7Published Mar 4, 2026

CVE-2026-3520Multer vulnerable to Denial of Service via uncontrolled recursion

Updated under an hour ago (Oct 26, 2026, 10:50 AM ET)

Does this affect you?

It affects expressjs multer and 2 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for expressjs multer

Exploited in the last 30 days

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: 8.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-674, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: openjs
NVD analysis: Modified
Record last updated: Jul 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

expressjs multer expressjs:multer (from the name)	before 2.1.1	CNA record
Red Hat Red Hat Developer Hub 1.8 redhat:rhdh	from 1774545605 not affected	CISA ADP
Red Hat Self-service automation portal 2 redhat:ansible_portal	2	CISA ADP
expressjs multer expressjs:multer	before 2.1.1	NVD

References

https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2vendor-advisory
https://www.cve.org/CVERecord?id=CVE-2026-3520third-party-advisory
https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752patch
https://cna.openjsf.org/security-advisories.htmlthird-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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.