Answer in brief
CVE-2025-71408 records a High severity (CVSS 8.5) vulnerability in NLTK < 3.9.3 Eval Injection via collocations.py Command-Line Arguments. The current sources do not mark it as known exploited. The current feed maps ntlk/ntlk (generic), nltk (pip), nltk (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps ntlk/ntlk (generic), nltk (pip), nltk (pypi). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| ntlk/ntlkgeneric | * | Not reported |
| nltkpip | <3.9.3 | 3.9.3 |
| nltkpypi | >=0 <3.9.3 | 3.9.3 |
Published upstream
Jul 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
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.
Quoted source text, attributed separately from HOL analysis.