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().
https://www.vulncheck.com/advisories/nltk-before-path-traversal-via-symlink-bypass
https://github.com/nltk/nltk/security/advisories/GHSA-p4rw-rvv2-7xwr
Published: 2026-08-25
Updated: 2026-08-25
Base Score: 5.4
Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:N/A:N
Severity: Medium
Base Score: 5.9
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Severity: Medium
Base Score: 8.2
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00297