CVE-2026-19484
CVE-2026-19484 · @fastify/busboy vulnerable to Denial of Service via oversized multipart boundary
This page contains facts from public vulnerability sources. Check the original advisory before updating.
@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.
CVSS 7.5 · High · EPSS 0.6% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
@fastify/busboy
- Versions
- ≥ 3.1.0, < 3.2.1: Affected (semver)
- 3.2.1: Not affected (semver)
Update to 3.2.1
@fastify/busboy npm
- Affected ranges
- SEMVER: ≥ 3.1.0, < 3.2.1
Update to 3.2.1