Link following in Natural Language Toolkit - #VU142771
Published: August 15, 2026
Vulnerability identifier: #VU142771
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-59
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper link resolution before file access in nltk.corpus.reader.ipipan, nltk.corpus.reader.crubadan, and nltk.corpus.reader.lin when processing attacker-influenced corpora under a trusted data root. A remote attacker can place a symlink inside the trusted corpus root that points to an external file and invoke normal corpus reader methods to disclose sensitive information.
Exploitation requires the application to process attacker-influenced corpora inside a trusted NLTK data root or trusted corpus directory with pathsec enforcement enabled.
Affected software
Natural Language Toolkit
Remediation
Install security update from vendor's website.
Natural Language Toolkit - update to 3.10.3