@fastify/busboy vulnerable to CRLF injection via multipart Content-Disposition filename and name

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74866
StatePUBLISHED
Assigneropenjs
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-21 09:16:40 UTC
Updated2026-08-21 13:18:19 UTC
Description@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.

Risk And Classification

Primary CVSS: v3.1 5.8 MEDIUM from ce714d77-add3-4f53-aff5-83d477b104bb

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

EPSS: 0.001930000 probability, percentile 0.093040000 (date 2026-08-21)

Problem Types: CWE-93 | CWE-93 CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

VersionSourceTypeScoreSeverityVector
3.1ce714d77-add3-4f53-aff5-83d477b104bbSecondary5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
3.1CNACVSS5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA @fastifybusboy @fastify/busboy affected 3.2.2 semver Not specified
CNA @fastifybusboy @fastify/busboy unaffected 3.2.2 semver Not specified

References

ReferenceSourceLinkTags
cna.openjsf.org/security-advisories.html ce714d77-add3-4f53-aff5-83d477b104bb cna.openjsf.org
github.com/fastify/busboy/security/advisories/GHSA-gxm5-99cw-xjw9 ce714d77-add3-4f53-aff5-83d477b104bb github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: tonghuaroot (en)

CNA: mcollina (en)

CNA: UlisesGascon (en)

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