medium5.3
CVE-2026-40347
python-multipart affected by Denial of Service via large multipart preamble or epilogue data
Impact
Python-Multipart is a streaming multipart parser for Python. Versions prior to 0.0.26 have a denial of service vulnerability when parsing crafted `multipart/form-data` requests with large preamble or epilogue sections. Upgrade to version 0.0.26 or later, which skips ahead to the next boundary candidate when processing leading CR/LF data and immediately discards epilogue data after the closing boundary.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | python-multipart | < 0.0.26 | 0.0.26 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Fastapiexpert | Python-Multipart | before 0.0.26 |