CVE-2025-71408
Description
A flaw was found in NLTK (Natural Language Toolkit). This eval injection vulnerability in the nltk.collocations module allows a local attacker to execute arbitrary Python code. By manipulating command-line arguments when collocations.py is invoked directly, an attacker can bypass validation and execute operating system commands. This can lead to significant impact on the system's confidentiality, integrity, and availability.
Statement
Conditions for Exploitation: Successful exploitation requires a highly specific and atypical execution scenario. An attacker must have direct control over command-line arguments, and the host environment must execute the module's internal script directly rather than importing NLTK as a standard programming library.
Usage Patterns and Likelihood: In standard deployments, NLTK is integrated into parent Python applications as an imported programming library rather than being run as a standalone command-line utility. Direct invocation of internal library scripts with untrusted command-line arguments is a highly uncommon and non-recommended deployment configuration, which significantly reduces the real-world likelihood of exploitation.
Affected Versions: This vulnerability affects NLTK versions prior to 3.9.3
Mitigation
To mitigate this vulnerability, avoid directly invoking the `nltk.collocations` module's internal script (`collocations.py`) with untrusted command-line arguments. In standard Red Hat deployments, NLTK is typically used as an imported library, which does not expose this vulnerability. If direct invocation is necessary, ensure that all command-line arguments are from trusted sources and are properly validated.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
In some cases, injectable code controls authentication; this may lead to a remote vulnerability.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Injected code can access resources that the attacker is directly prevented from accessing.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
When a product allows a user's input to contain code syntax, it might be possible for an attacker to craft the code in such a way that it will alter the intended control flow of the product. As a result, code injection can often result in the execution of arbitrary code. Code injection attacks can also lead to loss of data integrity in nearly all cases, since the control-plane data injected is always incidental to data recall or writing.
Non-Repudiation
Technical Impact: Hide Activities
Often the actions performed by injected control code are unlogged.
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