CVE-2026-40347 PUBLISHED

Python-Multipart affected by Denial of Service via large multipart preamble or epilogue data

Assigner: GitHub_M
Reserved: 10.04.2026 Published: 17.04.2026 Updated: 17.04.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 5.3

Product Status

Vendor Kludex
Product python-multipart
Versions
  • Version < 0.0.26 is affected

References

Problem Types

  • CWE-400: Uncontrolled Resource Consumption CWE
  • CWE-834: Excessive Iteration CWE