CVE-2026-40347— Python-Multipart affected by Denial of Service via large multipart preamble or epilogue data
Quick assessment
Affected
Kludex python-multipart
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
python-multipart是Marcelo Trylesinski个人开发者的一个Python的流式多部分解析器。 Python-Multipart 0.0.26之前版本存在安全漏洞，该漏洞源于解析特制的multipart/form-data请求时，大型前导或结尾部分可能导致拒绝服务。
Possible ATT&CK Techniques 1 AI
T1496 · Resource Hijacking
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I. Basic Information for CVE-2026-40347
Vulnerability Information
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Vulnerability Title
Python-Multipart affected by Denial of Service via large multipart preamble or epilogue data
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
python-multipart 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
python-multipart是Marcelo Trylesinski个人开发者的一个Python的流式多部分解析器。 Python-Multipart 0.0.26之前版本存在安全漏洞，该漏洞源于解析特制的multipart/form-data请求时，大型前导或结尾部分可能导致拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Kludex | python-multipart | < 0.0.26 | - |
|
II. Public POCs for CVE-2026-40347
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Pages for CVE-2026-40347 (1)
IV. Related Vulnerabilities
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V. Comments for CVE-2026-40347
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