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TI-2026-56780 Aliases CVE-2026-82333GHSA-535w-7cp7-47q4

multer vulnerable to Denial of Service via oversized array index in field names

Priority LOW 39CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 2 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00367 30th percentileScored 2026-11-07
Fix Partial multer (multer): 2.3.0multer (npm): 2.3.0Red Hat: 4 advisoriesRed Hat: 2 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
expressjsmulterbefore 2.3.02.3.0Patch availableCNA
—multer (npm)before 2.3.02.3.0Patch availableGHSA-535w-7cp7-47q4
  • multer Vendorexpressjs Affected before 2.3.0 Fixed in 2.3.0 Patch available CNA
  • multer (npm) Vendor— Affected before 2.3.0 Fixed in 2.3.0 Patch available GHSA-535w-7cp7-47q4

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:*before 2.3.0Vulnerableexpressjs
  • cpe:2.3:a:expressjs:multer:*:*:*:*:*:node.js:*:* Versions before 2.3.0 Vulnerable ·expressjs

Remediation

  • Fix · CNA multer (multer) Fixed in 2.3.0
  • Fix · GHSA-535w-7cp7-47q4 multer (npm) Fixed in 2.3.0 Advisory →

Red Hat 4 advisories

  • RHSA-2026:86675 Released 2026-10-21 · Red Hat rating Important
    Ansible plug-ins for Red Hat Developer Hub Product Release Update
    • Red Hat Ansible Automation Platform 2.2 registry.redhat.io/ansible-automation-platform/automation-portal
  • RHSA-2026:82151 Released 2026-10-13 · Red Hat rating Critical
    Ansible automation portal Red Hat Enterprise Linux Images
    • Red Hat Ansible Automation Platform 2.2 registry.redhat.io/ansible-automation-platform/bootc-automation-portal-rhel9
  • RHSA-2026:79088 Released 2026-10-08 · Red Hat rating Critical
    Red Hat Developer Hub 1.10.5 release.
    • Red Hat Developer Hub 1.10 registry.redhat.io/rhdh/rhdh-hub-rhel9, registry.redhat.io/rhdh/rhdh-rhel9-operator
Show 1 more Red Hat advisories
  • RHSA-2026:76788 Released 2026-10-06 · Red Hat rating Critical
    Red Hat Developer Hub 1.10.5 Plugin Catalog GA plugins release.
    • Red Hat Developer Hub 1.10 registry.redhat.io/rhdh/red-hat-developer-hub-backstage-plugin-lightspeed, registry.redhat.io/rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend, registry.redhat.io/rhdh/red-hat-developer-hub-backstage-plugin-orchestrator +4

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    multer 2.3.0

    4 records Highest priority Priority LOW 4 LOW

    Other records, highest priority first

    • TI-2026-53831 multer vulnerable to Denial of Service via crafted multipart field namesPriority LOW 39
    • TI-2026-53816 multer vulnerable to Denial of Service via file descriptor leak on aborted uploadsPriority LOW 39
    • TI-2026-53818 multer vulnerable to file size limit bypass via async fileFilter race conditionPriority LOW 17
    Show all 4 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Logging Subsystem for Red Hat OpenShiftAffectedNo fix planned: Will not fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Trusted Profile AnalyzerAffectedNo fix yet
Red Hat Ansible Automation Platform 2.2Fixed RHSA-2026:82151, RHSA-2026:86675
Red Hat Developer Hub 1.10Fixed RHSA-2026:76788, RHSA-2026:79088
Not affected: 7 products
  • Red Hat 3scale API Management Platform 2
  • Red Hat Developer Hub 1.10
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-82333
  2. 2026-10-03 Alias added: GHSA-535w-7cp7-47q4
  3. 2026-10-07 Fix available: RHSA-2026:76788 · Red Hat
  4. 2026-10-07 Fix available: Red Hat Developer Hub 1.10 · Red Hat
  5. 2026-10-09 Fix available: RHSA-2026:79088 · Red Hat
  6. 2026-10-09 Affected versions changed · Red Hat
  7. 2026-10-13 Fix available: Red Hat Ansible Automation Platform 2.2 · Red Hat
  8. 2026-10-13 Fix available: RHSA-2026:82151 · Red Hat
  9. 2026-10-21 Fix available: RHSA-2026:86675 · Red Hat
  10. 2026-10-21 Affected versions changed · Red Hat
  11. 2026-10-26 Affected versions changed · Red Hat
  12. 2026-10-29 Affected versions changed · Red Hat

References

Advisory 3

Other 4

  • TI-2026-03033 Multer vulnerable to Denial of Service via uncontrolled recursion CVSS 4.0HIGH 8.7
  • TI-2026-02853 Multer vulnerable to Denial of Service via incomplete cleanup CVSS 4.0HIGH 8.7
  • TI-2026-01995 Multer vulnerable to Denial of Service via resource exhaustion CVSS 4.0HIGH 8.7
  • TI-2026-53831 multer vulnerable to Denial of Service via crafted multipart field names CVSS 3.1HIGH 7.5
  • TI-2026-53816 multer vulnerable to Denial of Service via file descriptor leak on aborted uploads CVSS 3.1HIGH 7.5
  • TI-2026-04434 multer vulnerable to Denial of Service via deeply nested field names CVSS 3.1HIGH 7.5
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences