Headline
GHSA-59g5-xgcq-4qw3: Denial of service (DoS) via deformation `multipart/form-data` boundary
Summary
When parsing form data, python-multipart skips line breaks (CR \r or LF \n) in front of the first boundary and any tailing bytes after the last boundary. This happens one byte at a time and emits a log event each time, which may cause excessive logging for certain inputs.
An attacker could abuse this by sending a malicious request with lots of data before the first or after the last boundary, causing high CPU load and stalling the processing thread for a significant amount of time. In case of ASGI application, this could stall the event loop and prevent other requests from being processed, resulting in a denial of service (DoS).
Impact
Applications that use python-multipart to parse form data (or use frameworks that do so) are affected.
Original Report
This security issue was reported by:
- GitHub security advisory in Starlette on October 30 by @Startr4ck
- Email to
python-multipartmaintainer on October 3 by @mnqazi
Summary
When parsing form data, python-multipart skips line breaks (CR \r or LF \n) in front of the first boundary and any tailing bytes after the last boundary. This happens one byte at a time and emits a log event each time, which may cause excessive logging for certain inputs.
An attacker could abuse this by sending a malicious request with lots of data before the first or after the last boundary, causing high CPU load and stalling the processing thread for a significant amount of time. In case of ASGI application, this could stall the event loop and prevent other requests from being processed, resulting in a denial of service (DoS).
Impact
Applications that use python-multipart to parse form data (or use frameworks that do so) are affected.
Original Report
This security issue was reported by:
- GitHub security advisory in Starlette on October 30 by @Startr4ck
- Email to python-multipart maintainer on October 3 by @mnqazi
References
- GHSA-59g5-xgcq-4qw3
- https://nvd.nist.gov/vuln/detail/CVE-2024-53981
- Kludex/python-multipart@c4fe4d3