VulnSocial

CVE-2026-104851

LOWCVSS 8.8 · HIGH

Signal is active with 2 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD 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.

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0.0/ 10 priority

Sources & remediation

Other references
Weakness type (CWE)
CWE-94CWE-1336

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

NONE

Threat summary

  • 2 mentions across 1 observed day

What's happening

  • 2 total mentions across 1 day

Deep dive

Activity timeline2 mentions / 1d
01122Mentions · 2026-10-03: 210-03
Full discourse2 posts
  • Upwind Security MDR@UpwindMDR

    🚨HIGH - fsspec ReferenceFileSystem Jinja2 Template RCE (CVE-2026-104851) In fsspec ReferenceFileSystem, Kerchunk reference JSON fields are rendered via unrestricted Jinja2 template evaluation, letting attacker-supplied expressions execute Python when opening the reference FS. Malicious references can be provided inline or fetched from attacker-controlled URLs and trigger RCE via consumers like xarray. 👉Affected: fsspec/filesystem_spec >= 0.9.0, < 2026.6.0 | Upgrade to 2026.6.0

    0000047
    308 followersView on X
  • DFIR Lab@DFIR_Lab

    🚨 HIGH SEVERITY: CVE-2026-104851 (CVSS 8.8) fsspec Python framework vulnerable to code injection via malicious Kerchunk reference JSON. Affects versions 0.9.0-2026.6.0. ✅ Patch: Update to v2026.6.0 #CVE #Vulnerability #PatchNow https://t.co/3Vo5bzMJvE

    0000031
    142 followersView on X

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