UBUNTU-CVE-2026-104851

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Source
https://ubuntu.com/security/CVE-2026-104851
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-104851.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-104851
Upstream
Published
2026-10-05T00:00:00Z
Modified
2026-10-05T13:04:12Z
Severity
  • 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

fsspec is a specification and Python implementation framework for filesystem interfaces. From 0.9.0 until 2026.6.0, fsspec.implementations.reference.ReferenceFileSystem evaluates fields from Kerchunk reference JSON documents through unrestricted jinja2.Template(...).render(...) calls in _process_references1._render_jinja, _process_templates, and _process_gen in fsspec/implementations/reference.py. A document supplied inline or fetched from an attacker-controlled URL can provide template expressions that execute Python code when the reference filesystem is opened, including through consumers such as xarray, before referenced data is read. The _process_gen path is reached whenever a document includes a gen array, while the other paths depend on template-related options and values. This issue is fixed in version 2026.6.0.

References

Affected packages

Ubuntu:20.04:LTS / fsspec

Package

Name
fsspec
Purl
pkg:deb/ubuntu/fsspec?arch=source&distro=focal

Affected ranges

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

Affected versions

0.*
0.6.1-0.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-fsspec",
            "binary_version":  "0.6.1-0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-104851.json"

Ubuntu:22.04:LTS / fsspec

Package

Name
fsspec
Purl
pkg:deb/ubuntu/fsspec?arch=source&distro=jammy

Affected ranges

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

Affected versions

0.*
0.8.4-1
2022.*
2022.01.0-1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-fsspec",
            "binary_version":  "2022.01.0-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-104851.json"

Ubuntu:24.04:LTS / fsspec

Package

Name
fsspec
Purl
pkg:deb/ubuntu/fsspec?arch=source&distro=noble

Affected ranges

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

Affected versions

2023.*
2023.6.0-1
2023.9.2-1
2023.10.0-1
2024.*
2024.2.0-1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-fsspec",
            "binary_version":  "2024.2.0-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-104851.json"

Ubuntu:26.04:LTS / fsspec

Package

Name
fsspec
Purl
pkg:deb/ubuntu/fsspec?arch=source&distro=resolute

Affected ranges

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

Affected versions

2025.*
2025.3.2-1ubuntu1
2025.12.0-1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-fsspec",
            "binary_version":  "2025.12.0-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-104851.json"