CVE-2026-104851

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Source
https://cve.org/CVERecord?id=CVE-2026-104851
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-104851.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-104851
Aliases
Downstream
Published
2026-10-02T16:36:48Z
Modified
2026-10-04T02:46:03Z
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
Summary
fsspec: Server-Side Template Injection in ReferenceFileSystem leads to Remote Code Execution
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.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-1336",
        "CWE-94"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104851.json"
}
References

Affected packages

Git / github.com/fsspec/filesystem_spec

Affected ranges

Type
GIT
Repo
https://github.com/fsspec/filesystem_spec
Events
Introduced
c7d996685de74d2e3dc7f68b3c4722842a6914bc
Fixed
86438783f93b1398ef245b92f0e6063b445b611c
Fixed
a1c16ab3f07f354aa371c38f7b1b07ea7fd4c5c8
Fixed
a2457004d03e0312f715f90f58873de5ab195a37
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "0.9.0"
        },
        {
            "fixed":  "2026.6.0"
        }
    ],
    "source":  [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

0.*
0.9.0
2021.*
2021.04.0
2021.05.0
2021.06.0
2021.06.1
2021.07.0
2021.08.1
2021.09.0
2021.10.0
2021.10.1
2021.11.0
2021.11.1
2022.*
2022.01.0
2022.02.0
2022.10.0
2022.11.0
2022.3.0
2022.5.0
2022.7.0
2022.7.1
2022.8.0
2022.8.1
2022.8.2
2023.*
2023.1.0
2023.10.0
2023.12.0
2023.12.1
2023.12.2
2023.3.0
2023.4.0
2023.5.0
2023.6.0
2023.9.0
2023.9.1
2023.9.2
2024.*
2024.10.0
2024.12.0
2024.2.0
2024.3.0
2024.3.1
2024.5.0
2024.6.0
2024.6.1
2024.9.0
2025.*
2025.10.0
2025.12.0
2025.2.0
2025.3.0
2025.3.1
2025.3.2
2025.5.0
2025.5.1
2025.7.0
2025.9.0
2026.*
2026.1.0
2026.2.0
2026.3.0
2026.4.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-104851.json"