multer vulnerable to Denial of Service via incomplete cleanup of aborted uploads
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 fixed, 1 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat.
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.
Why it matters now
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| expressjs | multer | 2.0.0-alpha.1 to before 2.2.0; 3.0.0-alpha.1 to before 3.0.0-alpha.2 | 2.2.0, 3.0.0-alpha.2 | Patch available | CNA |
| — | multer (npm) | 2.0.0-alpha.1 to before 2.2.0 | 2.2.0 | Patch available | GHSA-3p4h-7m6x-2hcm |
| — | multer (npm) | 3.0.0-alpha.1 to before 3.0.0-alpha.2 | 3.0.0-alpha.2 | Patch available | GHSA-3p4h-7m6x-2hcm |
- multer Vendorexpressjs Affected 2.0.0-alpha.1 to before 2.2.0; 3.0.0-alpha.1 to before 3.0.0-alpha.2 Fixed in 2.2.0, 3.0.0-alpha.2 Patch available CNA
- multer (npm) Vendor— Affected 2.0.0-alpha.1 to before 2.2.0 Fixed in 2.2.0 Patch available GHSA-3p4h-7m6x-2hcm
- multer (npm) Vendor— Affected 3.0.0-alpha.1 to before 3.0.0-alpha.2 Fixed in 3.0.0-alpha.2 Patch available GHSA-3p4h-7m6x-2hcm
Remediation
- Fix · CNA multer (multer) Fixed in 2.2.0, 3.0.0-alpha.2
- Fix · GHSA-3p4h-7m6x-2hcm multer (npm) Fixed in 2.2.0 Advisory →
- Fix · GHSA-3p4h-7m6x-2hcm multer (npm) Fixed in 3.0.0-alpha.2 Advisory →
Red Hat 5 advisories
- RHSA-2026:73404 Released 2026-09-29 · Red Hat rating ImportantAnsible 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-2026:72712 Released 2026-09-28 · Red Hat rating ImportantAnsible plug-ins for Red Hat Developer Hub Product Release Update
- Red Hat Ansible Automation Platform 2.1 registry.redhat.io/ansible-automation-platform/automation-portal
- RHSA-2026:52768 Released 2026-08-10 · Red Hat rating ImportantRed Hat Developer Hub 1.9.8 release.
- Red Hat Developer Hub 1.9 registry.redhat.io/rhdh/rhdh-hub-rhel9
Show 2 more Red Hat advisories
- RHSA-2026:49642 Released 2026-08-03 · Red Hat rating ImportantRed Hat Developer Hub 1.10.3 release.
- Red Hat Developer Hub 1.10 registry.redhat.io/rhdh/rhdh-hub-rhel9, registry.redhat.io/rhdh/rhdh-rhel9-operator
- RHSA-2026:48126 Released 2026-07-29 · Red Hat rating ImportantRed Hat Developer Hub 1.10.3 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 2.2.0, 3.0.0-alpha.2
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-04434 multer vulnerable to Denial of Service via deeply nested field namesPriority LOW 39
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Logging Subsystem for Red Hat OpenShift | Affected | No fix yet |
| Red Hat Ansible Automation Platform 2.1 | Fixed | RHSA-2026:72712 |
| Red Hat Ansible Automation Platform 2.2 | Fixed | RHSA-2026:73404 |
| Red Hat Developer Hub 1.10 | Fixed | RHSA-2026:48126, RHSA-2026:49642 |
| Red Hat Developer Hub 1.9 | Fixed | RHSA-2026:52768 |
Not affected: 7 products
- Red Hat Developer Hub 1.10
- Red Hat Developer Hub 1.9
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Trusted Profile Analyzer
Timeline
- 2026-10-02 Threatist record created from CVE-2026-5038
- 2026-10-03 Alias added: GHSA-3p4h-7m6x-2hcm
References
More expressjs Multer vulnerabilities
- 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-2026-56780 multer vulnerable to Denial of Service via oversized array index in field names CVSS 3.1HIGH 7.5
- 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
Sources
- CVE-2026-5038 · CVE Program
- CVE-2026-5038 · NVD
- FIRST EPSS
- GHSA-3p4h-7m6x-2hcm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-5038 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences