Path Traversal in Nltk

CVE-2026-79676

NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using built-in open() instead of nltk.pathsec.open(), allowing symlinks to escape trusted roots. Attackers who stage symlinked corpus files under a trusted data root can disclose outside-root content through normal corpus reader methods like channels(), domains(), and synonyms().

Vulnerability class: Path Traversal (Directory Traversal)

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-79676?
CVE-2026-79676 is a medium-severity vulnerability in Nltk, classified under Path Traversal. CVSS score: 5.9/10. Published 2026-08-25.
How severe is CVE-2026-79676?
Medium severity. CVSS v3 base score is 5.9 out of 10.