Path Traversal in Nltk
CVE-2026-0847
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.009 (56.0th percentile) — read the EPSS interpretation.
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
- Nltk
- Nltk Nltk/nltk — versions unspecified
Weakness classification (CWE)
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2026-0847?
- CVE-2026-0847 is a high-severity vulnerability in Nltk, classified under Path Traversal. CVSS score: 7.5/10. Published 2026-03-04.
- How severe is CVE-2026-0847?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2026-0847 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.