Vulnerability in nltk (UBUNTU-CVE-2026-33236)
Summary
Vulnerability in nltk (UBUNTU-CVE-2026-33236). Data can be tampered with by attackers. Exploitable via subdir. Mitigation: upgrade to 2.0~b9-0ubuntu4.1~esm6 or later.
Original description
The description as published by the source.
NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, the NLTK downloader does not validate the subdir and id attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as ../), which can lead to arbitrary directory creation, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.
Source: OSV.dev (Open Source Vulnerabilities) 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 UBUNTU-CVE-2026-33236 has been found in nltk.
Attackers can target a specific entry point like subdir over the network to misuse the product.
Data can be tampered with by attackers.
What to do: upgrade nltk to 2.0b9-0ubuntu4.1esm6 or later.
If unsure, ask your IT team or search "nltk UBUNTU-CVE-2026-33236" on the vendor's site.
UBUNTU-CVE-2026-33236 (nltk)
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: subdir
Patched: 2.0~b9-0ubuntu4.1~esm6 — 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.
A vulnerability (unclassified) exists in nltk. Attackers reach the vulnerable code path via subdir without authentication.
Check the vendor advisory for the affected versions of nltk. Attack surface: subdir.
Severity: ?. Data can be tampered with by attackers.
Update to 2.0b9-0ubuntu4.1esm6.
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
-
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 2.0~b9-0ubuntu4.1~esm6ステージング環境で 2.0
b9-0ubuntu4.1esm6 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
References
- advisory ubuntu.com
- report ubuntu.com
- report cve.org
- report github.com
- report github.com