CVE-2026-34829 in Rack
Résumé (Anglaise)
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
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Responsable
GitHub_M
Réserver
30/03/2026
Divulgation
02/04/2026
Statut
Confirmé
Entrées
VulDB provides additional information and datapoints for this CVE:
| ID | Vulnérabilité | CWE | Exp | Con | CVE |
|---|---|---|---|---|---|
| 354945 | Rack Multipart déni de service | 400 | Non défini | Correctif officiel | CVE-2026-34829 |