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CVE-2026-2359: Expressjs Multer Security Vulnerability (CVSS 8.7)

CVE-2026-2359 is a high severity security vulnerability in Expressjs Multer with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 15, 2026

Quick answer

Direct answer

CVE-2026-2359 is a high severity security vulnerability in Expressjs Multer with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
8.7HIGH
EPSS probability
0.68%
Higher than 51 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Attack requirements (AT:N)No attack requirements
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Confidentiality (VC:N)No confidentiality impact
Integrity (VI:N)No integrity impact
Availability (VA:H)High availability impact

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

About Expressjs Multer

CVE-2026-2359 affects Expressjs Multer, a product from Expressjs. Before acting, confirm where Expressjs Multer runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability in Multer prior to version 2.1.0 allows an attacker to trigger a Denial of Service (DoS) by dropping connection during file upload, potentially causing resource exhaustion. Users should upgrade to version 2.1.0 to receive a patch. No known workarounds are available.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductExpressjs Multer
Affected versionsMulter before 2.1.0
PublishedFeb 27, 2026
Last modifiedJul 15, 2026
Added to CISA KEVNot listed
Assigning CNAce714d77-add3-4f53-aff5-83d477b104bb

How to detect it

  • Inventory every instance of Expressjs Multer and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Expressjs Multer named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Expressjs Multer to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-2359 is a high severity security vulnerability in Expressjs Multer with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Related CVEs

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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.

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Mar 9, 2026
All Expressjs CVEs in 2026
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