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HIGH

CVE-2026-82333

CVSS v3

7.5

HIGH

EPSS Score

0.5 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • multernpmall versions · fixed in 2.3.0

Vendor advisories

  • CVE-2026-82333 Red Hat Product Security4 products fixed · 23 known affected

    multer: Multer: Denial of Service via oversized array index in field names

    openshift-logging/vector-rhel9 as a component of Logging Subsystem for Red Hat OpenShift · firefox as a component of Red Hat Enterprise Linux 10 · firefox.src as a component of Red Hat Enterprise Linux 10

  • RHSA-2026:82151 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Ansible automation portal Red Hat Enterprise Linux Images

  • RHSA-2026:79088 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.10.5 release.

  • RHSA-2026:76788 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.10.5 Plugin Catalog GA plugins release.

Full record on NVD

Description

multer is a middleware for handling multipart/form-data in Node.js. A small multipart request with two specially crafted text field names can make multer's field parser synchronously iterate a maximum-length sparse array, blocking the event loop so the process cannot handle other requests. A large numeric array index in the first field allocates a maximum-length sparse array, and a second field with a non-numeric key then triggers a full-length iteration inside the append-field dependency. All versions before 2.3.0 are affected, and this is a remotely triggerable denial of service. multer 2.3.0 adds an opt-in fieldArrayIndexLimit option that rejects oversized array indexes. Upgrade to multer 2.3.0 and set limits.fieldArrayIndexLimit to the largest array index your application needs to remediate.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-08-28
Last Modified
2026-08-28

Frequently asked questions

What is CVE-2026-82333?

multer is a middleware for handling multipart/form-data in Node.js. A small multipart request with two specially crafted text field names can make multer's field parser synchronously iterate a maximum-length sparse array, blocking the event loop so the process cannot handle other requests. A large numeric array index in the first field allocates a maximum-length sparse array, and a second field with a non-numeric key then triggers a full-length iteration inside the append-field dependency. All versions before 2.3.0 are affected, and this is a remotely triggerable denial of service. multer 2.3.0 adds an opt-in fieldArrayIndexLimit option that rejects oversized array indexes. Upgrade to multer 2.3.0 and set limits.fieldArrayIndexLimit to the largest array index your application needs to remediate.

Is CVE-2026-82333 actively exploited?

Active exploitation of CVE-2026-82333 has not been confirmed. Its EPSS score was 0.5% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-82333?

CVE-2026-82333 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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