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CVE-2026-78683

NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization PUBLISHED

Description (CNA)

NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the TransitionParser.parse() method (nltk/parse/transitionparser.py). The method calls pickle_load() with the default restricted=False, routing deserialization through WarningUnpickler, which does not override find_class() and therefore permits arbitrary class resolution. When an application loads an attacker-crafted model file, embedded pickle gadget chains execute arbitrary Python code with the privileges of the user running the application. NLTK provides a RestrictedUnpickler for safe deserialization, but it is not used by production code paths. Fixed in 3.10.0.

Affected (CNA)

Vendor / productVersions
nltk / nltkaffected 0 before 3.10.0; unaffected 3.10.0

CWE

CWE-502

References

ADP enrichment

CISA-ADP

No English description supplied.