CVE-2026-40347: python-multipart affected by Denial of Service via large multipart preamble or epilogue data

April 15, 2026 (updated April 24, 2026)

A denial of service vulnerability exists when parsing crafted multipart/form-data requests with large preamble or epilogue sections.

References

github.com/Kludex/python-multipart/releases/tag/0.0.26
github.com/Kludex/python-multipart/security/advisories/GHSA-mj87-hwqh-73pj
github.com/advisories/GHSA-mj87-hwqh-73pj
nvd.nist.gov/vuln/detail/CVE-2026-40347

Code Behaviors & Features

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