GitHub Advisoryadvisory · npm
GHSA-gxm5-99cw-xjw9 @fastify/busboy vulnerable to CRLF injection via multipart Content-Disposition filename and name
MEDIUM
Official page ↗
- Aliases
- CVE-2026-74866
- Ecosystem
- npm
- Packages
- @fastify/busboy
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- Weaknesses
- CWE-93
- Reviewed
- 2026-10-05
Affected packages
• npm @fastify/busboy: < 3.2.2 → fixed in 3.2.2
Description
Impact
`@fastify/busboy` 3.2.1 and earlier retains a bare carriage return or line feed inside the parsed `Content-Disposition` parameters returned to the application. The multipart header parser ends a header line only on the two-byte `\r\n` sequence, so a lone CR or LF embedded in a part header is carried verbatim into the `filename` and field `name` delivered by the `file` and `field` events. An application that forwards the supplied filename or name into a CR/LF-sensitive sink cannot anticipate the embedded control character.
An attacker who uploads a file whose `filename` or field `name` contains a bare CR or LF can pollute filenames on disk when the upload is saved under its original name, inject forged lines into logs, or inject headers on a downstream hop that does not re-validate CR/LF, such as object-storage metadata or a proxied backend. Applications using `@fastify/busboy` directly, or through `@fastify/multipart` and its consumers, are affected.
Patches
Upgrade to `@fastify/busboy` 3.2.2 or later.
Workarounds
Validate or strip carriage return and line feed characters from the `filename` and field `name` before using them in any filesystem, logging, or outbound-header context.
Related
Alias · CVE (1)
- CVE-2026-74866 @fastify/busboy is a multipart form-data parser for Node.js. vulnerability
Weakness · CWE (1)
- CWE-93 Improper Neutralization of CRLF Sequences weakness
References
- https://github.com/fastify/busboy/security/advisories/GHSA-gxm5-99cw-xjw9 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-74866 advisory
- https://github.com/fastify/busboy/commit/cc7da17c5c88d79c314a9e149a79e5a00a6c23be web
- https://cna.openjsf.org/security-advisories.html web
- https://github.com/fastify/busboy package
- https://github.com/fastify/busboy/releases/tag/v3.2.2 web