MediumFix available
python-multipart — security advisory
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.
- Products
- python-multipart
- Affected versions
- 0.0.17-1, 0.0.17-2, 0.0.17-3, 0.0.17-4, 0.0.17-5, 0.0.20-1, 0.0.20-1.1, 0.0.20-1.1~deb13u1, 0.0.22-1, 0.0.26-1, 0.0.32-1, 0.0.5-3, 0.0.6-1, 0.0.9-1
- Fixed versions
- 0.0.26-1
- CVEs
- CVE-2026-40347
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:50 UTC · Revision 2
Source evidence
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.
osv:DEBIAN-CVE-2026-40347
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: Not specified
python-multipart
Fixed versions: 0.0.26-1
Complete source record
{
"id": "76fadc462f64136f7626ee70efeba5403a10afd19d574b4850b0d063217d1b2d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-40347",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-40347",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2026-40347",
"products": [
{
"name": {
"value": "python-multipart",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.0.17-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.17-2",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.17-3",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.17-4",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.17-5",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.20-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.20-1.1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.20-1.1~deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.22-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.26-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.32-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.5-3",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.6-1",
"evidence": "/affected/0/versions"
},
{
"value": "0.0.9-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "python-multipart",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "0.0.20-1",
"evidence": "/affected/1/versions"
},
{
"value": "0.0.20-1.1",
"evidence": "/affected/1/versions"
},
{
"value": "0.0.20-1.1~deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "0.0.22-1",
"evidence": "/affected/1/versions"
},
{
"value": "0.0.26-1",
"evidence": "/affected/1/versions"
},
{
"value": "0.0.32-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "python-multipart",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.0.26-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "0.0.20-1",
"evidence": "/affected/2/versions"
},
{
"value": "0.0.20-1.1",
"evidence": "/affected/2/versions"
},
{
"value": "0.0.20-1.1~deb13u1",
"evidence": "/affected/2/versions"
},
{
"value": "0.0.22-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-40347",
"aliases": [
"DEBIAN-CVE-2026-40347"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-multipart",
"purl": "pkg:deb/debian/python-multipart?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"0.0.17-1",
"0.0.17-2",
"0.0.17-3",
"0.0.17-4",
"0.0.17-5",
"0.0.20-1",
"0.0.20-1.1",
"0.0.20-1.1~deb13u1",
"0.0.22-1",
"0.0.26-1",
"0.0.32-1",
"0.0.5-3",
"0.0.6-1",
"0.0.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40347.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-multipart",
"purl": "pkg:deb/debian/python-multipart?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"0.0.20-1",
"0.0.20-1.1",
"0.0.20-1.1~deb13u1",
"0.0.22-1",
"0.0.26-1",
"0.0.32-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40347.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.0.26-1"
}
]
}
],
"package": {
"name": "python-multipart",
"purl": "pkg:deb/debian/python-multipart?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"0.0.20-1",
"0.0.20-1.1",
"0.0.20-1.1~deb13u1",
"0.0.22-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40347.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-27T09:47:44.130861221Z",
"provider": "osv",
"upstream": [
"CVE-2026-40347"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-40347"
]
},
"related_cves": [
{
"value": "CVE-2026-40347",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 461348,
"published_at": "2026-04-18T00:16:38.52+00:00"
}