High
python-multipart — security advisory
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.
- Products
- python-multipart
- Affected versions
- 0.0.20-1, 0.0.20-1.1, 0.0.26-1, 0.0.32-1, 0.0.5-2, 0.0.5-2ubuntu0.1~esm1, 0.0.5-3, 0.0.6-1, 0.0.9-1, 0.0.9-1ubuntu0.1~esm1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-42561
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:03 UTC · Revision 1
Source evidence
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.
osv:UBUNTU-CVE-2026-42561
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: Not specified
Complete source record
{
"id": "5f09e8d1dd0da8602b281fd211a9f9bb9aaa7b0a00fd47a25e80dd91a85734ba",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-42561",
"method": "structured",
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"summary": "Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.",
"evidence": "osv:UBUNTU-CVE-2026-42561",
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"modified": "2026-10-17T13:00:05.339921799Z",
"provider": "osv",
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"references": [
"https://ubuntu.com/security/CVE-2026-42561",
"https://www.cve.org/CVERecord?id=CVE-2026-42561",
"https://github.com/Kludex/python-multipart/security/advisories/GHSA-pp6c-gr5w-3c5g",
"https://github.com/Kludex/python-multipart/pull/267",
"https://github.com/Kludex/python-multipart/commit/3e64f5f8caba0e5d391b0c1ad0f1c2edf9e8f911"
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"source_id": "core-osv",
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"published_at": "2026-05-13T21:16:00+00:00"
}