{"answers":{"affected":"3 open source packages ship an affected version, including fsspec.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104851 exists.","fix":"Upgrade fsspec to 2026.6.0 or later.","what":"CVE-2026-104851 is a high-severity code injection vulnerability in fsspec filesystem_spec, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-104851 and fix it if it is affected.\n\nWhat it is: CVE-2026-104851 is a high-severity code injection vulnerability in fsspec filesystem_spec, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104851 exists.\n\nAffected packages and fixed versions:\n- fsspec (PyPI): affected from 0.9.0; fixed in 2026.6.0\n- fsspec (PyPI): affected from 0.9.0; fixed in 2026.6.0\n- fsspec (PyPI): affected from 0.9.0; fixed in 2026.6.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-104851/ (Markdown: https://insights.sbomify.com/CVE-2026-104851/index.md)","id":"CVE-2026-104851","markdown":"https://insights.sbomify.com/CVE-2026-104851/index.md","name":"CVE-2026-104851","record":{"aliases":["CLEANSTART-2026-ER50683","DEBIAN-CVE-2026-104851","ECHO-e799-0dd6-47ec","GHSA-27vj-qcqg-25rc","MINI-3hvw-xjwj-vwfx","MINI-3m3w-jfxf-x2j3","MINI-4v32-fxp5-32pf","MINI-6rxh-vm9f-f4jf","MINI-73f8-jffr-x7mw","MINI-7pgp-8g74-m6pj","MINI-83qw-r28g-m2qv","MINI-cr2w-pr8c-53g2","MINI-gg5p-8248-4cpw","MINI-mhv9-4qrq-8prh","MINI-pgw4-7wgw-wc65","MINI-q653-6mm4-9p9h","MINI-rw8h-fw2h-7w87","MINI-rxjp-h62h-xwf5","MINI-wj5w-5f83-x4rh","PYSEC-2026-4217","ROOT-APP-PYPI-CVE-2026-104851","UBUNTU-CVE-2026-104851","openSUSE-SU-2026:22028-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Python filesystem library","requires_auth":"none","summary":"Attackers can execute arbitrary Python code by supplying malicious Jinja2 templates in Kerchunk reference JSON documents processed by fsspec.","user_interaction":"required","vuln_class":"code_injection"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":8.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-94","name":"Improper Control of Generation of Code"},{"id":"CWE-1336","name":"Improper Neutralization of Special Elements Used in a Template Engine"}],"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.","ecosystems":["PyPI","openSUSE:Leap 16.0"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"fsspec: Server-Side Template Injection in ReferenceFileSystem leads to Remote Code Execution","id":"CVE-2026-104851","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"code_injection","year":"2026"},"n_packages":4,"n_references":6,"next":{"headline":"GraphQL Tools has prototype pollution in well-established utility function `mergeDeep`","id":"CVE-2026-104852"},"packages":[{"ecosystem":"PyPI","fixed":["2026.6.0"],"introduced":["0.9.0"],"last_affected":[],"package":"fsspec","purl":null,"source":"GHSA-27vj-qcqg-25rc"},{"ecosystem":"PyPI","fixed":["2026.6.0"],"introduced":["0.9.0"],"last_affected":[],"package":"fsspec","purl":"pkg:pypi/fsspec","source":"GHSA-27vj-qcqg-25rc"},{"ecosystem":"PyPI","fixed":["2026.6.0"],"introduced":["0.9.0"],"last_affected":[],"package":"fsspec","purl":"pkg:pypi/fsspec","source":"PYSEC-2026-4217"},{"ecosystem":"openSUSE:Leap 16.0","fixed":["2024.3.1-bp160.2.1"],"introduced":["0"],"last_affected":[],"package":"python-fsspec","purl":"pkg:rpm/opensuse/python-fsspec\u0026distro=openSUSE%20Leap%2016.0","source":"openSUSE-SU-2026:22028-1"}],"prev":{"headline":"MCP TypeScript SDK: OAuth client could send credentials to an authorization server chosen by the MCP server","id":"CVE-2026-104850"},"products":["filesystem_spec"],"published":"2026-10-02","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-05","vendors":["fsspec"]},"summary":"Attackers can execute arbitrary Python code by supplying malicious Jinja2 templates in Kerchunk reference JSON documents processed by fsspec.","url":"https://insights.sbomify.com/CVE-2026-104851/"}