CVE-2025-14009 | Zip Slip Vulnerability in nltk/nltk Leading to Remote Code Execution

Exp

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.

Published: 2026-02-18 Last update: 2026-03-06 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-14009 is rated High Exploit Risk (81.4/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.88%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2025-14009

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-14009

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-27 0.84% 0.88% +0.04%
2 2026-04-01 0.57% 0.84% +0.27%
3 2026-03-07 — 0.57% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-14009

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]

Weakness enumeration for CVE-2025-14009

GitHub Security Advisory for CVE-2025-14009

GHSA-7p94-766c-hgjp · Severity: critical · Ecosystem: pip — NLTK has a Zip Slip Vulnerability

OS Trackers for CVE-2025-14009

vendor priority summary link
alpine — CVE-2025-14009: 1 source package rows (py3-nltk); 1 state rows across 1 repos (edge-community); fixed 1, open 0. https://security.alpinelinux.org/vuln/CVE-2025-14009
debian not yet assigned CVE-2025-14009 not yet assigned priority: Debian including 1 source packages (nltk), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2025-14009
redhat high — https://access.redhat.com/security/cve/CVE-2025-14009
ubuntu high CVE-2025-14009 high priority: Ubuntu including 1 source packages (nltk), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): released 8, needed 1. https://ubuntu.com/security/CVE-2025-14009

Affected software / configurations for CVE-2025-14009

Vendor Product Version Raw CPE
nltk nltk < 3.9.3 cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

References for CVE-2025-14009

cvelogic Threat Intelligence