What’s Vulnerable › Vulnerabilities

CVE-2026-81726: NLTK through 3.10.3 Path Traversal via Model-Artifact APIs

• Severity: high (CVSS 7.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-08-27 · updated 2026-10-30
• Weakness: CWE-73

Description

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagger, and maxent parameter APIs when pathsec is enabled.

Affected products

• nltk: before 3.10.3 — fixed in 3.10.3
• nltk: through 3.10.3

How to fix

Upgrade to a fixed version: nltk 3.10.3. Check the vendor advisory for mitigations.

References

• https://github.com/nltk/nltk/security/advisories/GHSA-8mgp-746c-j5xp
• https://www.vulncheck.com/advisories/nltk-through-3.10.3-path-traversal-via-model-artifact-apis
• https://github.com/nltk/nltk/security/advisories/GHSA-8mgp-746c-j5xp

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