{"id":"CVE-2026-104851","revision":"f66b1cfeff8f4708b7c7aa3eae4681a9","records":[{"revision":"f66b1cfeff8f4708b7c7aa3eae4681a9","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-104851","aliases":[],"title":"fsspec: Server-Side Template Injection in ReferenceFileSystem leads to Remote Code Execution","description":"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.","state":0,"publishedAt":"2026-10-02T16:36:48.513+00:00","modifiedAt":"2026-10-05T20:03:36.502+00:00","affected":[{"ecosystem":"Vendor product","name":"filesystem_spec","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"fsspec\",\n                    \"product\": \"filesystem_spec\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 0.9.0, < 2026.6.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://github.com/fsspec/filesystem_spec/security/advisories/GHSA-27vj-qcqg-25rc","https://github.com/fsspec/filesystem_spec/pull/2029","https://github.com/fsspec/filesystem_spec/pull/2039","https://github.com/fsspec/filesystem_spec/commit/86438783f93b1398ef245b92f0e6063b445b611c","https://github.com/fsspec/filesystem_spec/commit/a1c16ab3f07f354aa371c38f7b1b07ea7fd4c5c8","https://github.com/fsspec/filesystem_spec/releases/tag/2026.6.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-104851","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-104851","identifiers":["CVE-2026-104851"]},"retained":false,"historicalAffected":[]}],"coverage":[]}