NLTK has a Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite
Summary
| CVE | CVE-2026-33236 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-20 23:16:47 UTC |
| Updated | 2026-07-10 12:16:40 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 8.1 HIGH from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
EPSS: 0.004980000 probability, percentile 0.392330000 (date 2026-07-12)
Problem Types: CWE-22 | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | CVSS | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H |
| 3.1 | [email protected] | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H |
| 3.1 | CNA | DECLARED | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Nltk | Nltk | affected <= 3.9.3 | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI 2.25 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI 3.3 | Not specified | Not specified |
| ADP | Red Hat | Lightspeed Core | Not specified | Not specified |
| ADP | Red Hat | OpenShift Lightspeed | Not specified | Not specified |
| ADP | Red Hat | Red Hat Ansible Automation Platform 2 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenShift AI RHOAI | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7 | [email protected] | github.com | Exploit, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:10184 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:37275 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a | [email protected] | github.com | Patch |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33236.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-33236 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| access.redhat.com/errata/RHSA-2026:19712 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-03-20T23:01:51.656Z | Reported to Red Hat. |
| ADP | 2026-03-20T22:47:10.308Z | Made public. |
Solutions
ADP: RHSA-2026:10184: Red Hat OpenShift AI 2.25
ADP: RHSA-2026:19712: Red Hat OpenShift AI 3.3
ADP: RHSA-2026:37275: Red Hat OpenShift AI 3.3
Workarounds
ADP: To mitigate this issue, ensure that any applications utilizing the NLTK downloader are configured to only interact with trusted XML index servers. Restrict network access for the application using NLTK to prevent connections to untrusted external resources. This operational control reduces the risk of an attacker controlling a malicious server to exploit the path traversal vulnerability. A service restart or reload may be required for network configuration changes to take effect.