SB2026061544 - Multiple vulnerabilities in multer

Description

This security bulletin contains information about 2 vulnerabilities.

1) Incomplete cleanup (CVE-ID: CVE-2026-5038)

CWE-ID: CWE-459 - Incomplete cleanup

CVSSv4: 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:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to incomplete cleanup in diskStorage when handling aborted or malformed multipart uploads. A remote attacker can send a malformed multipart upload or abort an upload to cause a denial of service.

Exploitation causes orphaned partial files to accumulate on disk.

2) Resource exhaustion (CVE-ID: CVE-2026-5079)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 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:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in the append-field dependency used by multipart form data processing when parsing deeply nested field names in bracket notation. A remote attacker can send a specially crafted multipart request to cause a denial of service.

A single HTTP request is sufficient to trigger the issue.

Remediation

Install update from vendor's website.

References

• https://github.com/expressjs/multer/security/advisories/GHSA-3p4h-7m6x-2hcm
• https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j