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

CVE-2025-47935 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

  • https://github.com/expressjs/multer/pull/1120
  • https://github.com/expressjs/multer/commit/2c8505f207d923dd8de13a9f93a4563e59933665

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2025-05-19 22:04:17 UTC
Updated
2025-06-08 07:19:19 UTC
GitHub reviewed
2025-05-19 22:04:17 UTC
NVD published
2025-05-19

EPSS Score

Score Percentile
0.18% 38.94%

CVSS Scores

Base score Version Severity Vector
7.5 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-44fp-w29j-9vj5 ↗
CVE CVE-2025-47935 ↗

CWEs

CWE id Name
CWE-401 Missing Release of Memory after Effective Lifetime

Credits

  • ctcpip (remediation_developer)
  • UlisesGascon (coordinator)
  • UnlimitedBytes (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm multer < 2.0.0 2.0.0 —

References

cvelogic Threat Intelligence