Low [CVE-2026-71514] Information disclosure via path traversal in CrubadanCorpusReader

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.txt mapping file, and opens the result with the builtin open() rather than the pathsec-validated opener, so os.path.join discards the root when that value is absolute and the read escapes the corpus directory without the containment check nltk.pathsec applies when ENFORCE is set.

An attacker who controls a corpus package can disclose file contents outside the corpus root through lang_freq, limited to paths ending in -3grams.txt whose contents parse as token count lines. A flaw was found in NLTK.

This occurs because a specially crafted input can bypass security checks, leading to unauthorized information disclosure. This Low impact vulnerability in NLTK's CrubadanCorpusReader allows for limited information disclosure via path traversal.

Exploitation requires an attacker to provide a specially crafted corpus package, restricting the attack surface. Red Hat severity: Low — CVSS 2.5 (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N).

Weakness: CWE-22. Red Hat lists Exploit Intelligence; Lightspeed Core; OpenShift Lightspeed; Red Hat Ansible Automation Platform 2; Red Hat OpenShift AI (RHOAI) as not affected.