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Fencer Vulns
medium 5.3

CVE-2026-5038 json

multer vulnerable to Denial of Service via incomplete cleanup of aborted uploads

published 2026-06-15 4 mo ago modified 2026-06-17 4 mo ago also GHSA-3p4h-7m6x-2hcm , EUVD-2026-36728

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Impact: multer versions 2.0.0-alpha.1 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service when using diskStorage. Aborted or malformed multipart uploads leave orphaned partial files on disk because the Readable.pipe() call does not propagate the stream destroy signal to the underlying fs.WriteStream. An attacker can exhaust disk space by triggering many aborted uploads, with no application bug required.

Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease). Both versions track in-flight write streams and clean them up on the abort path.

Workarounds: None.

Patch / fix

  • npm multer 2.2.0, 3.0.0-alpha.2
  • multer multer 2.2.0, 3.0.0-alpha.2

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-5038 updated cvss 7.5

multer: Multer: Denial of Service via aborted or malformed multipart uploads

  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/vector-rhel9
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2.1 ansible-automation-platform/automation-portal 1790254963
    fixed: vendor fix RHSA-2026:72712
  • Red Hat Ansible Automation Platform 2.2 ansible-automation-platform/bootc-automation-portal-rhel9 1790657374
    fixed: vendor fix RHSA-2026:73404
  • Red Hat Developer Hub 1.9 rhdh/rhdh-hub-rhel9 1785972843
    fixed: vendor fix RHSA-2026:52768
  • Red Hat Developer Hub 1.10 rhdh/rhdh-hub-rhel9 1785411652, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend 1785332487, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend 1785332825
    fixed: vendor fix RHSA-2026:48126
  • Red Hat Developer Hub 1.9 rhdh/rhdh-rhel9-operator 1785972533, rhdh/rhdh-operator-bundle 1785976147 Red Hat Developer Hub 1.10 rhdh/rhdh-rhel9-operator 1785411290, rhdh/rhdh-operator-bundle 1785415596, rhdh/rhdh-must-gather-rhel9 1784202439, rhdh/rhdh-rag-content-rhel9 1785162496, rhdh/red-hat-developer-hub-backstage-plugin-lightspeed 1785333413, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator 1785340831, +3 more
    not affected: vulnerable code not present
  • Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 thunderbird Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird
    not affected: vulnerable code not in execute path
  • Red Hat Enterprise Linux 10 firefox, thunderbird, fido-device-onboard Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm multer
>=2.0.0-alpha.1, <2.2.0
>=3.0.0-alpha.1, <3.0.0-alpha.2
2.2.0
3.0.0-alpha.2

Affected products

  • multer multer

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.