NLTK: Unsafe Pickle Deserialization in TransitionParser Allows Remote Code Execution

Date Sep 8, 2026

Type Vendor advisory

Signal Critical vendor advisory

Vendor / Product PyPI · nltk

CVE CVE-2026-78683

Critical vendor advisory CVE-2026-78683

Summary

NLTK: Unsafe Pickle Deserialization in TransitionParser Allows Remote Code Execution

Why it matters

GitHub has published a reviewed security advisory for nltk. Prioritize it with other application dependency updates, especially because EPSS places it in the 21% percentile.

Operator check

Check whether nltk is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available. CVSS score: 9.4. EPSS probability: 0.3%; percentile: 21%.

Sources

GitHub Advisory GHSA-rhp5-r9x4-f5g2 NVD — CVE-2026-78683 Source reference

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.

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