UBUNTU-CVE-2026-53538

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Source
https://ubuntu.com/security/CVE-2026-53538
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53538.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-53538
Upstream
Published
2026-06-22T18:16:00Z
Modified
2026-06-24T11:01:52.222134090Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:Pro:22.04:LTS / python-multipart

Package

Name
python-multipart
Purl
pkg:deb/ubuntu/python-multipart?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.0.5-2
0.0.5-2ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-multipart",
            "binary_version": "0.0.5-2ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53538.json"

Ubuntu:Pro:24.04:LTS / python-multipart

Package

Name
python-multipart
Purl
pkg:deb/ubuntu/python-multipart?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.0.5-3
0.0.6-1
0.0.9-1
0.0.9-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-multipart",
            "binary_version": "0.0.9-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53538.json"

Ubuntu:25.10 / python-multipart

Package

Name
python-multipart
Purl
pkg:deb/ubuntu/python-multipart?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.0.20-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-python-multipart",
            "binary_version": "0.0.20-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53538.json"

Ubuntu:26.04:LTS / python-multipart

Package

Name
python-multipart
Purl
pkg:deb/ubuntu/python-multipart?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.0.20-1
0.0.20-1.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-python-multipart",
            "binary_version": "0.0.20-1.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53538.json"