Path Traversal Vulnerability in NLTK by the Python Software Foundation
CVE-2026-33236

8.1HIGH

Key Information:

Vendor

Nltk

Status
Nltk
Vendor
CVE Published:
20 March 2026

What is CVE-2026-33236?

The NLTK (Natural Language Toolkit), a popular suite of open-source modules for Natural Language Processing, is vulnerable to a path traversal issue in versions 3.9.3 and earlier. The NLTK downloader improperly validates the 'subdir' and 'id' attributes from remote XML index files, allowing attackers to exploit a controlled remote index server. This exploitation can lead to arbitrary directory and file creation, as well as potential overwriting of critical files. A patch addressing this vulnerability has been implemented in commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a.

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Deploy the Patch

Affected Version(s)

nltk <= 3.9.3

References

https://github.com/nltk/nltk/security/advisories/GHSA-469...
x_refsource_CONFIRM
https://github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46...
x_refsource_MISC

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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