Bug 2515196 (CVE-2026-19484)

Summary: CVE-2026-19484 fastify/busboy: fastify/busboy: Denial of Service via oversized multipart boundary
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: amctagga, aoconnor, ataylor, bniver, dbruscin, ehugonne, flucifre, gmeno, groman, kvanderr, mbenjamin, mhackett, sostapov, vereddy
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in @fastify/busboy, a multipart form-data parser. A remote, unauthenticated attacker can exploit this by sending a specially crafted multipart request with an oversized boundary. This can cause the Node.js event loop to stall, leading to a CPU-bound loop that consumes significant processing resources. Consequently, a single small request can keep a core busy and deny service to other requests handled by the same process.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-13 09:21:13 UTC 
@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.