Code Injection in nltk (CVE-2025-14009)
Summary
Code injection in nltk (CVE-2025-14009). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 3.9.3 or later.
Original description
The description as published by the source.
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: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-14009 has been found in nltk.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade nltk to 3.9.3 or later.
If unsure, ask your IT team or search "nltk CVE-2025-14009" on the vendor's site.
CVE-2025-14009 (nltk) — CWE-94 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Patched: 3.9.3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Arbitrary code execution (CWE-94) exists in nltk.
Check the vendor advisory for the affected versions of nltk.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to 3.9.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'nltk' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'nltk' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
nltkを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade nltk to 3.9.3ステージング環境で 3.9.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2025-14009 nltk
- Ubuntu UBUNTU-CVE-2025-14009 nltk Fixed in: 2.0~b9-0ubuntu4.1~esm5
References
- advisory nvd.nist.gov
- advisory github.com
- exploit huntr.com
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web access.redhat.com
- web access.redhat.com
- web bugzilla.redhat.com
- web security.access.redhat.com