FKIE_CVE-2026-104851

Vulnerability from fkie_nvd - Published: 2026-10-02 17:17 - Updated: 2026-10-02 18:47
Severity
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
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
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/commit/86438783f93b1398ef245b92f0e6063b445b611c
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/commit/a1c16ab3f07f354aa371c38f7b1b07ea7fd4c5c8
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/pull/2029
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/pull/2039
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/releases/tag/2026.6.0
security-advisories@github.comhttps://github.com/fsspec/filesystem_spec/security/advisories/GHSA-27vj-qcqg-25rc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "filesystem_spec",
          "vendor": "fsspec",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.9.0, \u003c 2026.6.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-104851",
  "lastModified": "2026-10-02T18:47:49.947",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-02T17:17:03.763",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/commit/86438783f93b1398ef245b92f0e6063b445b611c"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/commit/a1c16ab3f07f354aa371c38f7b1b07ea7fd4c5c8"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/pull/2029"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/pull/2039"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/releases/tag/2026.6.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/fsspec/filesystem_spec/security/advisories/GHSA-27vj-qcqg-25rc"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        },
        {
          "lang": "en",
          "value": "CWE-1336"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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