Starlette is a lightweight ASGI (Asynchronous Server Gateway Interface) framework/toolkit, designed for building async web services in Python. In versions 0.47.1 and below, when parsing a multi-part form with large files (greater than the default max spool size) starlette will block the main thread to roll the file over to disk. This blocks the event thread which means the application can't accept new connections. The UploadFile code has a minor bug where instead of just checking for self._in_memory, the logic should also check if the additional bytes will cause a rollover. The vulnerability is fixed in version 0.47.2.
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Tue, 29 Jul 2025 12:30:00 +0000
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Description | Starlette is a lightweight ASGI (Asynchronous Server Gateway Interface) framework/toolkit, designed for building async web services in Python. In versions 0.47.1 and below, when parsing a multi-part form with large files (greater than the default max spool size) starlette will block the main thread to roll the file over to disk. This blocks the event thread which means the application can't accept new connections. The UploadFile code has a minor bug where instead of just checking for self._in_memory, the logic should also check if the additional bytes will cause a rollover. The vulnerability is fixed in version 0.47.2. | |
Title | Starlette has possible denial-of-service vector when parsing large files in multipart forms | |
Weaknesses | CWE-770 | |
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2025-07-21T20:06:03.818Z
Updated: 2025-07-22T19:54:24.784Z
Reserved: 2025-07-16T23:53:40.508Z
Link: CVE-2025-54121

Updated: 2025-07-22T19:54:21.128Z

Status : Awaiting Analysis
Published: 2025-07-21T20:15:41.827
Modified: 2025-07-22T13:05:40.573
Link: CVE-2025-54121
