CVE-2025-14009

Published Feb 18, 2026

Last updated 8 days ago

CVSS high 8.8
Ubuntu

Overview

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.
Source
security@huntr.dev
NVD status
Modified
Products
nltk

Risk scores

CVSS 3.1

Type
Secondary
Base score
8.8
Impact score
5.9
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

CVSS 3.0

Type
Secondary
Base score
10
Impact score
6
Exploitability score
3.9
Vector string
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity
CRITICAL

Weaknesses

security@huntr.dev
CWE-94
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
CWE-94

Social media

Hype score
Not currently trending

  1. BREAKING: Critical NLTK bug CVE-2025-14009 in Ubuntu 14.04-24.04 allows arbitrary code execution via malicious zip files, users urged to update packages immediately. https://t.co/YUWRnaudAa

    @threatcluster

    28 Apr 2026

    203 Impressions

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  2. 🔴 NLTK, Code Injection, #CVE-2025-14009 (Critical) https://t.co/JAXvC0RQmW

    @dailycve

    7 Mar 2026

    92 Impressions

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  3. `NLTK` is vulnerable to a path traversal flaw (CVE-2025-14009) in its downloader, enabling arbitrary file writes via crafted zip archives. Mitigation details: #nltk #infosec #pathtraversal https://t.co/JQw9mXXq0y

    @pulsepatchio

    20 Feb 2026

    36 Impressions

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  4. A path traversal vulnerability (CVE-2025-14009) affects the `NLTK` downloader, allowing arbitrary file writes. Evaluate `nltk` use with untrusted data. #Python #PathTraversal #infosec https://t.co/gmFoLpCv9H

    @pulsepatchio

    20 Feb 2026

    40 Impressions

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  5. CVE-2025-14009 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.ext… https://t.co/4KfoSbl5bF

    @CVEnew

    18 Feb 2026

    126 Impressions

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  6. 🔴 CVE-2025-14009 - Critical 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 per... https://t.co/lOegNOoKGN https://t.co/wUKtQpU050

    @TheHackerWire

    18 Feb 2026

    49 Impressions

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Configurations

Related CVEs

  1. A local privilege escalation vulnerability exists in snap-confine, a set-capabilities core component used internally by Canonical snapd to construct the secure execution environment for snap applications. This vulnerability uniquely affects versions of snap-confine configured with set-capabilities (rather than standard set-uid-root installations). Due to a flaw in how privilege boundaries or security sandboxes are initialized when the binary runs under limited ambient capabilities, a local, unprivileged attacker can exploit this behavior to bypass intended restrictions and execute arbitrary code. Successful exploitation allows the local user to elevate their privileges to full root authority.•CVE-2026-8933
  2. DD-WRT Stack-Based Buffer Overflow Vulnerability•CVE-2021-27137
  3. An input validation and injection vulnerability exists in Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools). The client constructs APT source files (such as /etc/apt/sources.list.d/ubuntu-.list or their DEB822 equivalents) using data received directly from the contract server response via the directives.suites[] and directives.aptURL fields. Because the client utilizes Python's str.format() to write these files without performing escaping, validation, or newline character filtering, a malicious or tampered contract response containing embedded newline (\n) characters can successfully inject arbitrary, attacker-controlled deb configuration lines into root-owned APT sources. When combined with the unvalidated additionalPackages[] field—which is passed positionally into a root-executed apt-get install command—an attacker capable of spoofing or manipulating the contract response (e.g., via a compromised internal infrastructure, an intercepted connection utilizing a trusted CA, or local logical bugs) can force the client to fetch and install malicious packages. This ultimately leads to arbitrary code execution with root privileges on the affected system. This component is preinstalled on supported Ubuntu Server releases and auto-attaches by default on cloud provider Ubuntu Pro images.•CVE-2026-11386
  4. In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page. A similar hole however remains if the modified PDE points to a non-leaf page. In this case the gfn can be made to match, but the role does not match: the original large 2MB page creates a kvm_mmu_page with direct=1, while the new 4KB needs a kvm_mmu_page with direct=0. However, kvm_mmu_get_child_sp() does not compare the role, and therefore reuses the page. The next step is installing a leaf (4KB) SPTE on the new path which records an rmap entry under the gfn resolved by the walk. But when that child is zapped its parent kvm_mmu_page has direct=1 and kvm_mmu_page_get_gfn() computes the gfn for the 4KB page as sp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[] in older kernels). It therefore fails to remove the recorded entry. When the memslot is dropped the shadow page is freed but the rmap entry survives, as in the scenario that was already fixed. Code that later walks that gfn (dirty logging, MMU notifier invalidation, and so on) dereferences an sptep that lies in the freed page, causing the use-after-free.•CVE-2026-53359
  5. In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.•CVE-2026-12252

References

Sources include official advisories and independent security research.