Answer in brief
CVE-2026-74866 records a Unknown severity vulnerability in @fastify/busboy vulnerable to CRLF injection via multipart Content-Disposition filename and name. The current sources do not mark it as known exploited. The current feed maps @fastify/busboy/@fastify/busboy (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps @fastify/busboy/@fastify/busboy (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| @fastify/busboy/@fastify/busboygeneric | >=0 <3.2.2 | 3.2.2 |
Published upstream
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 21, 2026
@fastify/busboy is a multipart form-data parser for Node.js. Its multipart part-header parser splits header lines only on the two-byte carriage-return line-feed sequence, so a lone carriage return or line feed embedded in a part header is not treated as a line break and is carried verbatim into the parsed Content-Disposition filename and field name handed to the application. An attacker who uploads a file whose filename or field name contains a bare carriage return or line feed can inject control characters into consumers that trust the parser to return clean values, enabling filesystem filename pollution, log forging, or header injection when the value is forwarded to a carriage-return-sensitive sink. All versions of @fastify/busboy up to and including 3.2.1 are affected. The issue is fixed in version 3.2.2, which rejects any header line that still contains a bare carriage return or line feed. Users should upgrade to 3.2.2, and consumers such as @fastify/multipart should bump their @fastify/busboy dependency to pull in the fix.
Quoted source text, attributed separately from HOL analysis.