CVE-2026-19484

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.

Weakness classification

• ce714d77-add3-4f53-aff5-83d477b104bb: CWE-835

Primary references

• ce714d77-add3-4f53-aff5-83d477b104bb — Third Party Advisory
• ce714d77-add3-4f53-aff5-83d477b104bb — Vendor Advisory