UBUNTU-CVE-2026-53537

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Source
https://ubuntu.com/security/CVE-2026-53537
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53537.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-53537
Upstream
Published
2026-06-22T18:16:00Z
Modified
2026-06-29T13:50:41.305867088Z
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
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/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, parseoptionsheader parsed Content-Disposition (and Content-Type) headers with email.message.Message, which transparently applies RFC 2231/5987 decoding. The extended parameter syntax (filename*=charset'lang'value, name*=..., and the filename0/filename1 continuation form) is decoded and surfaced under the bare filename/name key, and overrides the plain parameter when both are present. RFC 7578 ยง4.2 explicitly forbids the filename* form in multipart/form-data. Components that follow RFC 7578, or that do not implement RFC 2231/5987 decoding for multipart/form-data (WAFs, proxies, gateways), may interpret such a header differently. An attacker can exploit that difference to smuggle a different field name or filename past an upstream inspector to the backend. 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-2026-53537.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-2026-53537.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-2026-53537.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-2026-53537.json"