Vulnerability Details CVE-2026-14535
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 24.0%
CVSS Severity
CVSS v3 Score 8.8
Products affected by CVE-2026-14535
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cpe:2.3:a:trailofbits:fickling:0.0.1
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cpe:2.3:a:trailofbits:fickling:0.0.2
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cpe:2.3:a:trailofbits:fickling:0.0.3
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cpe:2.3:a:trailofbits:fickling:0.0.4
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cpe:2.3:a:trailofbits:fickling:0.0.5
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cpe:2.3:a:trailofbits:fickling:0.0.6
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cpe:2.3:a:trailofbits:fickling:0.0.7
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cpe:2.3:a:trailofbits:fickling:0.0.8
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cpe:2.3:a:trailofbits:fickling:0.1.0
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cpe:2.3:a:trailofbits:fickling:0.1.1
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cpe:2.3:a:trailofbits:fickling:0.1.10
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cpe:2.3:a:trailofbits:fickling:0.1.11
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cpe:2.3:a:trailofbits:fickling:0.1.2
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cpe:2.3:a:trailofbits:fickling:0.1.3
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cpe:2.3:a:trailofbits:fickling:0.1.4
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cpe:2.3:a:trailofbits:fickling:0.1.5
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cpe:2.3:a:trailofbits:fickling:0.1.6
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cpe:2.3:a:trailofbits:fickling:0.1.7
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cpe:2.3:a:trailofbits:fickling:0.1.8
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cpe:2.3:a:trailofbits:fickling:0.1.9