@fastify/busboy is a multipart form-data parser. In versions 3.1.0 through 3.2.0, a remote unauthenticated attacker can stall the Node.js event loop by sending a multipart request whose boundary is crafted to a specific length. The vendored streaming search stores its skip table in a fixed 256 entry byte array, and a boundary of exactly 252 bytes makes the search needle 256 bytes, which truncates the default skip distance to zero and turns the search into a CPU bound loop on a small body. A single small request can keep one core busy and deny service to other requests handled by the same process. The issue is fixed in @fastify/busboy 3.2.1, which widens the skip table so the skip distance is preserved. Users should upgrade to 3.2.1.
History

Thu, 03 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
First Time appeared Fastify fastify\/busyboy
CPEs cpe:2.3:a:fastify:fastify\/busyboy:*:*:*:*:*:node.js:*:*
Vendors & Products Fastify fastify\/busyboy

Tue, 18 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-606
References
Metrics threat_severity

None

threat_severity

Important


Sat, 15 Aug 2026 01:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 13 Aug 2026 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Fastify
Fastify busboy
Vendors & Products Fastify
Fastify busboy

Thu, 13 Aug 2026 09:30:00 +0000

Type Values Removed Values Added
Description @fastify/busboy is a multipart form-data parser. In versions 3.1.0 through 3.2.0, a remote unauthenticated attacker can stall the Node.js event loop by sending a multipart request whose boundary is crafted to a specific length. The vendored streaming search stores its skip table in a fixed 256 entry byte array, and a boundary of exactly 252 bytes makes the search needle 256 bytes, which truncates the default skip distance to zero and turns the search into a CPU bound loop on a small body. A single small request can keep one core busy and deny service to other requests handled by the same process. The issue is fixed in @fastify/busboy 3.2.1, which widens the skip table so the skip distance is preserved. Users should upgrade to 3.2.1.
Title @fastify/busboy vulnerable to Denial of Service via oversized multipart boundary
Weaknesses CWE-1322
CWE-835
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published: 2026-08-13T08:50:47.361Z

Updated: 2026-08-13T14:27:01.128Z

Reserved: 2026-08-10T16:17:07.041Z

Link: CVE-2026-19484

cve-icon Vulnrichment

Updated: 2026-08-13T14:26:57.068Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-13T10:17:11.640

Modified: 2026-09-03T19:10:52.893

Link: CVE-2026-19484

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-13T08:50:47Z

Links: CVE-2026-19484 - Bugzilla