AIKIDO-2026-258789
@fastify/busboy is vulnerable to Denial of Service (DoS)
75
High Risk
This Affects:
@fastify/busboyTL;DR
The vendored streaming multipart search stores its default skip distance in a fixed 256-entry byte array. A multipart boundary of exactly 252 bytes makes the search needle 256 bytes, so the skip-table entry wraps to zero and the search degenerates into a CPU-bound loop over a small body. A single small unauthenticated request can stall the Node.js event loop and deny service to other requests handled by the same process. The fix widens the skip table so the computed skip distance is preserved.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and your application parses untrusted multipart/form-data with @fastify/busboy.
Background info
@fastify/busboy is vulnerable to Denial of Service (DoS) in versions 3.1.0 - 3.2.0.
How to fix this
Upgrade the @fastify/busboy library to the patch version.
Links
GitHub Release
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SOC 2Compliant
ISO 27001Compliant