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HIGH severity

GHSA-44fp-w29j-9vj5 — multer

HIGHFix: expressjs/multer#1120

GHSA-44fp-w29j-9vj5 is a high-severity (CVSS 7.5) CWE-401 vulnerability in multer. A fix is available for multer — see the affected versions and patch details below.

Multer vulnerable to Denial of Service via memory leaks from unclosed streams

Also known asCVE-2025-47935
Published
May 19, 2025
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-44fp-w29j-9vj5.

EPSS Exploitation Probability

via FIRST.org ↗
0.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-44fp-w29j-9vj5 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

7Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream
multernpm
24.8Mdownloads / week

Description

Impact

Multer <2.0.0 is vulnerable to a resource exhaustion and memory leak issue due to improper stream handling. When the HTTP request stream emits an error, the internal busboy stream is not closed, violating Node.js stream safety guidance.

This leads to unclosed streams accumulating over time, consuming memory and file descriptors. Under sustained or repeated failure conditions, this can result in denial of service, requiring manual server restarts to recover. All users of Multer handling file uploads are potentially impacted.

Patches

Users should upgrade to 2.0.0

Workarounds

None

References

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmmulterall versions2.0.0npm install multer@2.0.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for multer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update multer to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-44fp-w29j-9vj5 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact Multer <2.0.0 is vulnerable to a resource exhaustion and memory leak issue due to improper stream handling. When the HTTP request stream emits an error, the internal `busboy` stream is not closed, violating Node.js stream safety guidance. This leads to unclosed streams accumulating over time, consuming memory and file descriptors. Under sustained or repeated failure conditions, this can result in denial of service, requiring manual server restarts to recover. All users of Multer handling file uploads are potentially impacted. ### Patches Users should upgrade to `2.0.0` ### Wo
O3 Security · Impact-Aware SCA

Is GHSA-44fp-w29j-9vj5 in your dependencies?

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GHSA-44fp-w29j-9vj5: multer DoS (High 7.5) | O3 Security