CVE-2025-14009
A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.79%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.79% probability · 54th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-94
- Affected
- nltk/nltk
- Source
- security@huntr.dev
References
- https://huntr.com/bounties/49ecbc02-054e-4470-b2e0-b267936cc4e4Exploit, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/security/cve/CVE-2025-14009
- https://bugzilla.redhat.com/show_bug.cgi?id=2440724
- https://huntr.com/bounties/49ecbc02-054e-4470-b2e0-b267936cc4e4Exploit, Third Party Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-14009.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.