id: PYSEC-2026-2150
published: "2026-07-04T14:16:29.063Z"
modified: "2026-07-13T05:48:44.938730Z"
aliases:
- CVE-2026-14535
- GHSA-cffv-grgg-g429
details: In Trail of Bits fickling versions up to and including 0.1.11, the UnsafeImportsML analysis pass unconditionally calls AnalysisContext.shorten_code(node) on every import node it inspects, regardless of whether the import is flagged as unsafe. This call registers the shortened code representation in the shared AnalysisContext.reported_shortened_code set. When the MLAllowlist analysis pass subsequently runs, it calls the same shorten_code() method, receives already_reported=True for every import, and executes a continue statement that skips its allowlist check entirely. This renders MLAllowlist dead code for all imports — it never evaluates whether an import is in the ML allowlist or not. The MLAllowlist pass was designed to catch imports of modules outside the known-safe ML ecosystem (torch, numpy, transformers, etc.) that slip past the UnsafeImports denylist. With MLAllowlist inoperative, any standard library module not in the UNSAFE_IMPORTS denylist can be invoked via pickle deserialization while fickling's check_safety() returns LIKELY_SAFE. The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate, meaning a LIKELY_SAFE verdict causes the payload to be deserialized and executed. The root cause is shared mutable state between independently-correct analysis passes — UnsafeImportsML works as designed in isolation, MLAllowlist works as designed in isolation, but the shared reported_shortened_code set causes UnsafeImportsML to poison MLAllowlist's deduplication logic.
affected:
- package:
    name: fickling
    ecosystem: PyPI
    purl: pkg:pypi/fickling
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: "0"
    - fixed: 0.1.12
  versions:
  - 0.0.1
  - 0.0.2
  - 0.0.3
  - 0.0.4
  - 0.0.5
  - 0.0.6
  - 0.0.7
  - 0.0.8
  - 0.1.10
  - 0.1.11
  - 0.1.2
  - 0.1.3
  - 0.1.4
  - 0.1.5
  - 0.1.6
  - 0.1.7
  - 0.1.8
  - 0.1.9
  ecosystem_specific: {}
references:
- type: ADVISORY
  url: https://github.com/trailofbits/fickling/releases/tag/v0.1.12
- type: FIX
  url: https://github.com/trailofbits/fickling/commit/41ce7cb01edd97072994039574a2301ebb3f463d
- type: FIX
  url: https://github.com/trailofbits/fickling/pull/278
- type: EVIDENCE
  url: https://github.com/trailofbits/fickling/security/advisories/GHSA-cffv-grgg-g429
severity:
- type: CVSS_V3
  score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H