# NLTK 3.9.4 through 3.10.2 contains a path traversal vulnerability in CrubadanCorpusReader. \_load_lang_ngrams joins the corpus root with crubadan_code, the column-0 value read from the corpus table....

Advisory record · `GHSA-cv22-g7mw-8v73`

- **Identifiers:** `GHSA-cv22-g7mw-8v73` · `CVE-2026-71514` · `PYSEC-2026-3790`
- **State:** Confirmed
- **Severity:** CVSS 2.0 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-22](https://cwe.mitre.org/data/definitions/22.html)
- **Tags:** [Path traversal](https://agentprime.io/advisories/tag/path-traversal.md)
- **Published:** 22 Aug 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 22 Aug 2026, 14:16 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `nltk` (PyPI): affected `>=3.9.4, <3.10.3`; fixed in `3.10.3`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> NLTK versions 3.9.4 through 3.10.2 are vulnerable to path traversal in CrubadanCorpusReader. An attacker who controls a corpus package can read files outside the corpus directory through lang_freq, but only files whose names end in -3grams.txt and whose contents parse as token count lines. Upgrade to NLTK 3.10.3, which contains the fix. The source gives few details on the exact conditions beyond this.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 2.0 Low, CVSS 4.0: `CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`, from CNA (VulnCheck)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0017, the 6th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:10 UTC: First seen by agentprime
- 31 Oct 2026, 14:10 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/PYSEC-2026-3790)

## Sources

- [GitHub Advisory Database: GHSA-cv22-g7mw-8v73](https://github.com/advisories/GHSA-cv22-g7mw-8v73)
- [OSV: GHSA-cv22-g7mw-8v73](https://osv.dev/vulnerability/GHSA-cv22-g7mw-8v73)
- <https://www.vulncheck.com/advisories/nltk-through-path-traversal-via-crubadancorpusreader-pathsec-bypass>
- <https://github.com/nltk/nltk/blob/v3.10.2/nltk/corpus/reader/crubadan.py#L90-L98>
- <https://github.com/nltk/nltk/commit/10d34b3f4fe3fec74b76527a409eb0acbac2e8ab>
- <https://github.com/nltk/nltk>
- <https://github.com/advisories/GHSA-cv22-g7mw-8v73>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-cv22-g7mw-8v73>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-cv22-g7mw-8v73/>. Everything for agents: <https://agentprime.io/llms.txt>.