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DEBIAN-CVE-2026-53538

Type: advisorySource: OSV1 source record

Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, QuerystringParser treated ; as a field separator in application/x-www-form-urlencoded bodies, in addition to &. The WHATWG URL standard, modern browsers, and Python's urllib.parse (since the CVE-2021-23336 fix) treat only & as a separator. This creates a parser differential: the same bytes are tokenized into different fields than a WHATWG compliant intermediary would produce, allowing an attacker to smuggle extra form fields past an upstream body inspecting component. This vulnerability is fixed in 0.0.30.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-53538

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-53538

python-multipart

Source reference: /affected/0/package/name

Affected versions
0.0.17-1

Source reference: /affected/0/versions

0.0.17-2

Source reference: /affected/0/versions

0.0.17-3

Source reference: /affected/0/versions

0.0.17-4

Source reference: /affected/0/versions

0.0.17-5

Source reference: /affected/0/versions

0.0.20-1

Source reference: /affected/0/versions

0.0.20-1.1

Source reference: /affected/0/versions

0.0.20-1.1~deb13u1

Source reference: /affected/0/versions

0.0.22-1

Source reference: /affected/0/versions

0.0.26-1

Source reference: /affected/0/versions

0.0.32-1

Source reference: /affected/0/versions

0.0.5-3

Source reference: /affected/0/versions

0.0.6-1

Source reference: /affected/0/versions

0.0.9-1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

python-multipart

Source reference: /affected/1/package/name

Affected versions
0.0.20-1

Source reference: /affected/1/versions

0.0.20-1.1

Source reference: /affected/1/versions

0.0.20-1.1~deb13u1

Source reference: /affected/1/versions

0.0.22-1

Source reference: /affected/1/versions

0.0.26-1

Source reference: /affected/1/versions

0.0.32-1

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

python-multipart

Source reference: /affected/2/package/name

Affected versions
0.0.20-1

Source reference: /affected/2/versions

0.0.20-1.1

Source reference: /affected/2/versions

0.0.20-1.1~deb13u1

Source reference: /affected/2/versions

0.0.22-1

Source reference: /affected/2/versions

0.0.26-1

Source reference: /affected/2/versions

Fixed versions
0.0.32-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "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-2026-53538.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-2026-53538.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "0.0.32-1"
          }
        ]
      }
    ],
    "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",
      "0.0.26-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-53538.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]
Related CVEs
CVE-2026-53538

Source reference: /upstream

Publisher severity

low

Source reference: /severity/0/score

Event
#81912 · Revision 1
Added to Heist Feed
Publisher date
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