CVE-2026-19484

Summary

@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.

Affected Software

Weaknesses

• CWE-835: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
• CWE-1322: CWE-1322: Use of Blocking Code in Single-threaded, Non-blocking Context

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://github.com/fastify/busboy/security/advisories/GHSA-xjh9-v7x6-24jw
• https://cna.openjsf.org/security-advisories.html

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