CVE-2026-19484@fastify/busboy vulnerable to Denial of Service via oversized multipart boundary
Updated under an hour ago ()
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It affects @fastify/busboy and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
@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 (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-835, CWE-1322
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- openjs
- NVD analysis
- Analyzed
- Record last updated
- Aug 13, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
@fastify/busboy @fastify/busboy fastify_busboy:fastify_busboy (from the name) | from 3.1.0 before 3.2.1; 3.2.1 not affected | CNA record |
fastify fastify/busyboy fastify:fastify/busyboy | from 3.1.0 before 3.2.1 | NVD |
References
- https://github.com/fastify/busboy/security/advisories/GHSA-xjh9-v7x6-24jwvendor-advisory
- https://cna.openjsf.org/security-advisories.htmlthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.