CVEvulnerability
CVE-2025-71408
8.5 HIGH
Official page ↗
- Status
- Analyzed
- Published
- 2026-07-24
- Last modified
- 2026-10-08
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.5 HIGH — CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 7.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-95
Description
NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or sanitization, enabling an attacker to supply a Python expression that escapes the intended attribute lookup and executes arbitrary code including OS commands via the os module.
Affected configurations
• nltk nltk (< 3.9.3)
Related
Weakness · CWE (1)
- CWE-95 Improper Neutralization of Directives in Dynamically Evaluated Code weakness
References
- https://aydinnyunus.github.io/2026/06/07/command-injection-nltk-collocations-eval/ Exploit, Press/Media Coverage, Third Party Advisory
- https://github.com/nltk/nltk/commit/66f14096d952ec8f04934f515e027534bd4eb0ac Patch
- https://github.com/nltk/nltk/pull/3465 Issue Tracking, Patch
- https://github.com/nltk/nltk/releases/tag/3.9.3 Release Notes
- https://www.vulncheck.com/advisories/nltk-eval-injection-via-collocations-py-command-line-arguments Patch, Third Party Advisory