CVE-2026-3520

Multer vulnerable to Denial of Service via uncontrolled recursion

CVSS 4.0 8.7 HIGHEUVD CVSS 4.0 8.7 CVSS 4.0 · ce714d77-add3-4f53-aff5-83d477b104bb · Secondary 8.7 HIGHCVSS 3.1 · [email protected] · Primary 7.5 HIGHCVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary 7.5 HIGHCVSS_V4 Publisher rating HIGHFixed by multer 2.1.1KEV status unknown

Original advisory

cve-program · CVE-2026-3520

Published

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.

Read the publisher's advisory

euvd · EUVD-2026-9423

Published

Read the publisher's advisory

nvd · CVE-2026-3520

Published

Read the publisher's advisory

osv · GHSA-5528-5vmv-3xc2

Published

### Impact A vulnerability in Multer versions < 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow. ### Patches Users should upgrade to `2.1.1` ### Workarounds None ### Resources - https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2 - https://www.cve.org/CVERecord?id=CVE-2026-3520 - https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752 - https://cna.openjsf.org/security-advisories.html

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Affected versions, risk and source history

cve-program · CVE-2026-3520

Published

multer

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "expressjs",
                    "product": "multer",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "versionType": "semver",
                            "status": "affected",
                            "version": "0",
                            "lessThan": "2.1.1"
                        }
                    ],
                    "packageURL": "pkg:npm/multer"
                }

Original source record · Cite this exact observation · Complete original publisher JSON

euvd · EUVD-2026-9423

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Mar 4, 2026, 4:17:18 PM

dateUpdated: Jul 15, 2026, 1:03:04 AM

3 related source bulletins · separate from aliases

RHSA-2026:6802: Red Hat Security Advisory: Red Hat Developer Hub 1.9.3 release.

CVE-2025-61140 · CVE-2025-69873 · CVE-2026-1615 · CVE-2026-2359 · CVE-2026-3304 · CVE-2026-3520 · CVE-2026-24046 · CVE-2026-25153 · CVE-2026-25639 · CVE-2026-25679 · CVE-2026-25896 · CVE-2026-26278 · CVE-2026-27606 · CVE-2026-27942 · CVE-2026-33186

RHSA-2026:6174: Red Hat Security Advisory: Red Hat Developer Hub 1.8.5 release.

CVE-2025-61140 · CVE-2026-2359 · CVE-2026-3304 · CVE-2026-3520 · CVE-2026-24046 · CVE-2026-25153 · CVE-2026-25639 · CVE-2026-25896 · CVE-2026-26278 · CVE-2026-27606 · CVE-2026-27942 · CVE-2026-33186

WID-SEC-W-2026-3046: IBM Concert: Mehrere Schwachstellen

CVE-2019-19921 · CVE-2021-23337 · CVE-2024-3651 · CVE-2024-39338 · CVE-2024-45590 · CVE-2025-13465 · CVE-2025-15284 · CVE-2025-15599 · CVE-2025-22874 · CVE-2025-47273 · CVE-2025-47907 · CVE-2025-52881 · CVE-2025-53643 · CVE-2025-55184 · CVE-2025-58056 · CVE-2025-58188 · CVE-2025-58189 · CVE-2025-61723 · CVE-2025-61730 · CVE-2025-64649 · CVE-2025-64756 · CVE-2025-67221 · CVE-2025-68121 · CVE-2025-68146 · CVE-2026-0540 · CVE-2026-2327 · CVE-2026-23490 · CVE-2026-23897 · CVE-2026-2391 · CVE-2026-23949 · CVE-2026-24486 · CVE-2026-25528 · CVE-2026-25547 · CVE-2026-25639 · CVE-2026-25990 · CVE-2026-26007 · CVE-2026-26019 · CVE-2026-26996 · CVE-2026-27142 · CVE-2026-27212 · CVE-2026-27699 · CVE-2026-27903 · CVE-2026-27904 · CVE-2026-28684 · CVE-2026-29063 · CVE-2026-29181 · CVE-2026-2950 · CVE-2026-31808 · CVE-2026-31900 · CVE-2026-32274 · CVE-2026-32288 · CVE-2026-32597 · CVE-2026-32630 · CVE-2026-32887 · CVE-2026-32952 · CVE-2026-33186 · CVE-2026-33532 · CVE-2026-33750 · CVE-2026-33814 · CVE-2026-33816 · CVE-2026-33916 · CVE-2026-34043 · CVE-2026-34073 · CVE-2026-34077 · CVE-2026-3520 · CVE-2026-35469 · CVE-2026-35515 · CVE-2026-3627 · CVE-2026-39823 · CVE-2026-39825 · CVE-2026-39826 · CVE-2026-39892 · CVE-2026-39984 · CVE-2026-40175 · CVE-2026-40179 · CVE-2026-40181 · CVE-2026-40190 · CVE-2026-40347 · CVE-2026-41066 · CVE-2026-41182 · CVE-2026-41238 · CVE-2026-41239 · CVE-2026-41240 · CVE-2026-41305 · CVE-2026-41324 · CVE-2026-41425 · CVE-2026-41481 · CVE-2026-41488 · CVE-2026-41602 · CVE-2026-41636 · CVE-2026-42151 · CVE-2026-42154 · CVE-2026-42198 · CVE-2026-42211 · CVE-2026-42338 · CVE-2026-42342 · CVE-2026-42561 · CVE-2026-42577 · CVE-2026-43870 · CVE-2026-44405 · CVE-2026-44431 · CVE-2026-44432 · CVE-2026-44486 · CVE-2026-44487 · CVE-2026-44488 · CVE-2026-44492 · CVE-2026-44494 · CVE-2026-44496 · CVE-2026-44728 · CVE-2026-4539 · CVE-2026-45409 · CVE-2026-45736 · CVE-2026-46625 · CVE-2026-4800 · CVE-2026-4923 · CVE-2026-4926 · CVE-2026-7246 · CVE-2026-8723

No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.

Original source record · Cite this exact observation · Complete original publisher JSON

nvd · CVE-2026-3520

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Modified

Weakness classifications: CWE-674 · CWE-770

Original publisher date fields

published: 2026-03-04T17:16:22.610

lastModified: 2026-07-15T02:21:00.833

1 source CPE criteria · context only

cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Original source record · Cite this exact observation · Complete original publisher JSON

osv · GHSA-5528-5vmv-3xc2

Published

multer

npm

SEMVER · introduced 0 → fixed 2.1.1

Original source record · Cite this exact observation · Complete original publisher JSON