CVE-2026-104851

{"id": "CVE-2026-104851", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-104851", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-10-05T20:03:10.746838Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "fsspec", "product": "filesystem_spec", "versions": [{"status": "affected", "version": ">= 0.9.0, < 2026.6.0"}]}]}], "published": "2026-10-02T17:17:03.763", "references": [{"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", "source": "security-advisories@github.com"}, {"url": "https://github.com/fsspec/filesystem_spec/security/advisories/GHSA-27vj-qcqg-25rc", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-94"}, {"lang": "en", "value": "CWE-1336"}]}], "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."}], "lastModified": "2026-10-05T20:17:09.373", "sourceIdentifier": "security-advisories@github.com"}