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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (36.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/nltk/nltk/security/advisories/GHSA-p4rw-rvv2-7xwr (Exploit, vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/nltk-before-path-traversal-via-symlink-bypass (Third Party Advisory, third-party-advisory)
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.