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VulnerabilityPublished Updated

CVE-2025-14009: nltk/nltk · Code Injection

Affects nltk/nltkSource CVE Database V5

0

Not known to be exploited · CVSS 10.0 Critical.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.0 base score
10.0Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.0% chance of exploitation in 30 days – higher than 63% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
nltknltk/nltkAffected
  • ≥ unspecified, ≤ latest
Fixed in–

AI-suggested

Red Hat advisories reference this CVE but do not indicate an official fix for nltk. Until a patch is available, users should avoid downloading and extracting untrusted packages with the NLTK downloader. Consider manual validation of downloaded content or restricting network access for environments using NLTK downloader. Monitor official vendor advisories for updates and apply patches promptly once released.

Description

A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py uses zipfile.extractall() without performing path validation or security checks. This allows attackers to craft malicious zip packages that, when downloaded and extracted by NLTK, can execute arbitrary code. The vulnerability arises because NLTK assumes all downloaded packages are trusted and extracts them without validation. If a malicious package contains Python files, such as __init__.py, these files are executed automatically upon import, leading to remote code execution. This issue can result in full system compromise, including file system access, network access, and potential persistence mechanisms.

References

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