Path Traversal in Nltk

CVE-2026-63312

NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can read arbitrary local files regardless of the ENFORCE setting, including sensitive system files and application credentials.

Vulnerability class: Path Traversal (Directory Traversal)

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-63312?
CVE-2026-63312 is a high-severity vulnerability in Nltk, classified under Path Traversal. CVSS score: 7.5/10. Published 2026-08-22.
How severe is CVE-2026-63312?
High severity. CVSS v3 base score is 7.5 out of 10.