CVE-2026-0847: Path Traversal in nltk/nltk
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/nltkto a version that resolves this vulnerability.Fixed in 3.9.3-1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-0847?
CVE-2026-0847 is classified as a high-severity vulnerability due to its potential for arbitrary file read access.
How do I fix CVE-2026-0847?
To mitigate CVE-2026-0847, upgrade NLTK to version 3.9.3 or later which addresses the path traversal issue.
What software versions are affected by CVE-2026-0847?
NLTK versions up to and including 3.9.2 are affected by CVE-2026-0847, allowing path traversal vulnerabilities.
What does CVE-2026-0847 allow an attacker to do?
CVE-2026-0847 allows an attacker to read arbitrary files on the server by exploiting path traversal in specific CorpusReader classes.
Which classes in NLTK are vulnerable according to CVE-2026-0847?
The vulnerable classes include WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader in NLTK.